Category Archives: sea level

Smoking Kills, so does Climate Change

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A translation of the IPCC 5th Assessment Report Summary for Policymakers

WHO: The Intergovernmental Panel on Climate Change

WHAT: Summary for policy makers of their 2000 page 5th Assessment Report (AR5) of the state of the climate and climate science.

WHEN: 27 September 2013

WHERE: On the IPCC website

TITLE: Climate Change 2013: The Physical Science Basis Summary for Policymakers (open access)

There’s a lot of things not to like about the way the IPCC communicates what they do, but for me the main one is that they speak a very specific dialect of bureaucrat that no-one else understands unless they’ve also worked on UN things and speak the same sort of acronym.

The worst bit of this dialect of bureaucrat is the words they use to describe how confident they are that their findings are correct. They probably believe they’re being really clear, however they use language that none of the rest of us would ever use and it means their findings make little sense without their ‘very likely = 90-100% certain’ footnote at the front.

So now that we’ve established that the UN doesn’t speak an understandable form of English, what does the report actually say? It works its way through each of the different climate systems and how they’re changing because humans are burning fossil fuels.

As you can see from this lovely graph, each of the last three decades has been noticeably warmer than the proceeding one, and the IPCC are 66% sure that 1983-2012 was the warmest 30 year period in 1,400 years.

Decade by decade average temperatures (Y axis is change in Celsius from base year of 1950) (from paper)

Decade by decade average temperatures (Y axis is change in Celsius from base year of 1950) (from paper)

One of the reasons I really like this graph is you can see how the rate of change is speeding up (one of the key dangers with climate change). From 1850 through to around 1980 each decade’s average is touching the box of the average before it, until after the 80s when the heat shoots up much more rapidly.

The report did have this dig for the deniers though: ‘Due to natural variability, trends based on short records are very sensitive to the beginning and end dates and do not in general reflect long-term climate trends’. Which is UN bureaucrat for ‘when you cherry pick data to fit your denier talking points you’re doing it wrong’.

Looking at regional atmospheric trends, the report notes that while things like the Medieval Warm Period did have multi-decadal periods of change, these changes didn’t happen across the whole globe like the warming currently being measured.

In the oceans, the top layer has warmed (the top 75m) by 0.11oC per decade from 1971 to 2010, and more than 60% of the carbon energy we’ve pumped into the atmosphere since 1971 has been stored in the top layer, with another 30% being stored in the ocean below 700m.

This extra heat is not just causing thermal expansion, it’s speeding up sea level rise, which the IPCC are 90% certain increased from 1901 to 2010 from 1.7mm per year to 3.2mm per year. This is now happening faster than the past two millenniums. Yes, sea level is rising faster than it has for the last 2,000,000 years so you might want to sell your waterfront property sooner, rather than later.

The extra carbon has also made it harder to live in the ocean if you own a shell, because the acidity of the ocean has increased by 26% which makes shells thinner and harder to grow.

On the glaciers and the ice sheets, the IPCC is 90% certain that the rate of melting from Greenland has increased from 34Gigatonnes (Gt) of ice per year to 215Gt of ice after 2002. Yes, increased from 34Gt to 215Gt – it’s melting six times faster now thanks to us.

For Antarctica, the IPCC is 66% certain that the rate of ice loss has increased from 30Gt per year to 147Gt per year, with most of that loss coming from the Northern Peninsula and West Antarctica. Worryingly, this ice loss will also include the parts of Antarctica that are gaining ice due to natural variability.

And at the North Pole, Santa is going to have to buy himself and his elves some boats or floating pontoons soon, because the IPCC have found ‘multiple lines of evidence support[ing] very substantial Artctic warming since the mid-20th Century’. Sorry Santa!

As for the carbon we’ve been spewing into the atmosphere since the 1850s, well, we’re winning that race too! ‘The atmospheric concentrations of carbon dioxide, methane and nitrous oxide have increased to levels unprecedented in at least the last 800,000 years’. Congratulations humanity – in the last century and a half, we’ve changed the composition of the atmosphere so rapidly that this hasn’t been seen in 800,000 years!

Methane levels have gone up by 150%, and I’m undecided as to whether that means I should eat more beef to stop the cows from farting, or if it means we raised too many cows to be steaks in the first place…

This is the part of the report where we get into the one excellent thing the IPCC did this time around – our carbon budget. I’m not sure whether they realised that committing to reduce certain percentages by certain years from different baselines meant that governments were able to shuffle the numbers to do nothing and make themselves look good at the same time, but this is a promising step.

I’ve written about the very excellent work of Kevin Anderson at the Tyndall Centre in the UK before, but the basic deal with a carbon budget is this: it doesn’t matter when we burn the carbon or how fast, all the matters is the total emissions in the end. You can eat half the chocolate bar now, and half the chocolate bar later, but you’re still eating a whole bar.

Our budget to have a 2/3 chance of not going beyond dangerous climate change is 1,000Gt of carbon and so far we’ve burnt 545Gt, so we’re more than halfway there. All of this leads to the conclusion that ‘human influence on the climate system is clear. This is evident from the increasing greenhouse gas concentrations in the atmosphere, positive radiative forcing, observed warming and understanding of the climate system.’

What observations you may ask? Scientists have made progress on working out how climate change pumps extreme weather up and makes it worse. They also got it right for the frequency of extreme warm and cold days, which if you live in North America was the hot extremes winning 10:1 over the cold extremes. Round of applause for science everyone!

Warming with natural forcing vs human forcing and how it lines up with the observations (from paper)

Warming with natural forcing vs human forcing and how it lines up with the observations (from paper)

They’re also 95% sure that more than half of the observed global surface warming from 1951 is from humanity. So next time there’s a nasty heatwave that’s more frequent than it should be, blame humans.

The report does also point out though that even though the heat records are beating the cold records 10-1, this doesn’t mean that snow disproves climate change (sorry Fox News!). There will still be yearly and decade by decade by variability in how our planet cooks which will not be the same across the whole planet. Which sounds to me like we’re being warmed in an uneven microwave. For instance, El Niño and La Niña will still be big influencers over the Pacific and will determine to a great extent the variability in the Pacific North West (yeah, it’s still going to rain a lot Vancouver).

For those that were fans of the film The Day After Tomorrow, there’s a 66% chance the Atlantic Meridional Circulation will slow down, but only a 10% chance it will undergo an abrupt change or collapse like it did in the film, so you’re not going to be running away from a flash freezing ocean any time this century.

The report then runs through the different scenarios they’ve decided to model that range from ‘we did a lot to reduce carbon emissions’ to ‘we did nothing to reduce carbon emissions and burned all the fossil fuels’. Because this is the IPCC and they had to get EVERYONE to agree on each line of the report (I’m serious, they approved it line by line, which has to be the most painful process I can think of) the scenarios are conservative in their estimations, not measuring tipping points (which are really hard to incorporate anyway). So their ‘worst case scenario’ is only 4.0oC of surface warming by 2100.

Representative Concentration Pathway (RCP) Scenarios from the IPCC AR5

Representative Concentration Pathway (RCP) Scenarios from the IPCC AR5

Now, obviously ‘only’ 4oC of climate change by the end of the century is still pretty unbearable. There will still be a lot of hardship, drought, famine, refugee migration and uninhabitable parts of the planet with 4oC. However, once we get to 4oC, it’s likely to have triggered tipping points like methane release from permafrost, so 4oC would be a stopping point towards 6oC even if we ran out of carbon to burn. And 6oC of course, as you all hear me say frequently is mass extinction time. It’s also the point at which even if humanity did survive, you wouldn’t want to live here anymore.

The paper finishes up with a subtle dig at the insanity of relying on geoengineering, pointing out that trying to put shade reflectors into orbit or artificially suck carbon out of the air has a high chance of going horribly wrong. They also point out that if we did manage large scale geoegineering and it then broke down, re-releasing that carbon back into the atmosphere would super-cook the planet really quickly.

The moral of this 36 page ‘summary’ is that it’s us guys. We’re as certain that we’ve done this as we are that smoking causes cancer. We have burned this carbon and it’s changed the chemical energy balance of the atmosphere and if we don’t stop burning carbon we’re going to cook the whole planet. Seriously. So let’s finally, actually stop burning carbon.

Extreme Overachiever Decade 2001-2010

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The World Meteorological Organisation global climate report for last decade shows it winning all the most extreme awards.

WHO: The World Meteorological Organisation (WMO) in conjunction with these international experts and meteorological and climate organisations.

WHAT: The Global Climate Report for the decade 2001-2010

WHEN: July 2013

WHERE: Online at the WMO website

TITLE: The Global Climate 2001-2010 A Decade of Climate Extremes (open access)

The World Meteorological Organisation (WMO) recently released their wrap up of the last decade’s worth of global weather related data. Now, as you will all remember, climate is the long term trend of the weather (generally over a 30 year period) but it’s also important to keep track of the decade to decade trends, if not because 10 is a nice round number to deal with.

So what did the last decade’s report card look like? Turns out 2001-2010 was an overachiever when it came to records and extremes, which is bad news for all of us, really. The last decade was the warmest on record for overall temperatures and the speed of warming has amped up as well. The long term warming trend is 0.062oC/decade, but since 1970 it’s sped up to 0.17oC/decade.

Decade by decade temperature record (from report)

Decade by decade temperature record (from report)

If you only look at land surface temperatures 2007 held the record for hottest with 0.95oC above average, with 2004 the ‘least warm’ (there’s no long term cold records happening here) at 0.68oC above average.

If you look at sea surface temperatures, 2003 wins with 0.40oC above average and 2008 was the least warm at 0.26oC above average. The warmest year in the Northern Hemisphere was 2007 at 1.13oC above average and in the Southern Hemisphere 2005 wins with 0.67oC.

When it comes to rain, it’s a mixed bag. There were places that got more rain, there were places with drought, there were more extremes. South America was wetter than normal, Africa was drier than normal. Overall, 2002 was the driest year of the decade and 2010 was the wettest. The problem with rain patterns changing with climate change is that the location and the time frame changes. Instead of slow soaking rains, it’s extremes of dry spells followed by flash flooding.

The patterns of El Niño and La Niña switched back quite a lot during the decade, with El Niño generally creating warmer trends and La Niña creating cooler trends.

El Niño and La Niña trends for sea surface temperatures (from report)

El Niño and La Niña trends for sea surface temperatures (from report)

To qualify as an extreme event, an event needs to result in 10 or more people dying, 100 or more people being affected, a declaration of a state of emergency and the need for international assistance, which I think is a pretty high bar. But of course, since the last decade was overachieving, there were 400 disasters of this scale that killed more than 1million people.

Weather disasters represented 88% of these extreme events and the damage from these events have increased significantly as well as seeing a 20% increase in casualties from the previous decade. The extra casualties have been from some extreme increases in certain categories like heatwaves. In 1991-2000 6,000 people died from heatwaves. In 2001-2010 that jumped to 136,000 people.

The price of extreme weather events has also gone up with 7,100 hydrometeorological events carrying a price tag of $US1trillion and resulting in 440,000 deaths over the decade. It’s also estimated that 20million people worldwide were displaced, so this was probably our first decade of a sizable number of climate refugees. Internal displacement will be one of the biggest factors as people move away from the more extreme parts of their country to the places where it still rains (eg. from Arizona to Oregon).

Tropical storms were a big issue, with the report noting ‘a steady increase in the exposure of OECD countries [to tropical cyclones] is also clear’. It’s nice to see them point out that issues around extreme weather are not a developing world problem because they don’t have the infrastructure to deal with them, shown through the flooding in Germany and Australia last decade.

There was also a special shout-out to my homeland of Australia, for the epic heatwave of 2009 where I experienced 46oC in Melbourne and can attest to it not being fun. Of course, that epic heatwave was beaten by 2013’s new extreme map colour. However I noted Australia was getting pretty much all of the extreme weather effects over the decade. Ouch.

Australia – can’t catch a break (compiled from report)

Australia – can’t catch a break (compiled from report)

Even for the category of ‘coldwaves’ where the Northern Hemisphere saw an increase in freak snowstorms, the average temperature for the winter was still +0.52oC warmer than average.

Last decade was also setting lots of records in the cryosphere (frozen part of the planet). 2005-2010 had the five lowest Arctic sea ice records which have been declining in extent and volume at a disturbingly rapid rate in what is commonly known as the Arctic Death Spiral. There’s been an acceleration of loss of mass from Greenland and the Antarctic ice sheets and a decrease in all global glaciers.

Arctic Death Spiral (from report)

Arctic Death Spiral (from report)

The World Glacier Monitoring Service describes the glacier melt rate and cumulative loss as ‘extraordinary’ and noted that glaciers are currently so far away from their equilibrium state that even without further warming they’re still going to keep melting. Oh, and last decade won the record for loss of snow cover too.

Declining snow cover (from report)

Declining snow cover (from report)

Sea level has started rising faster at a rate of 3mm/yr last decade, which is double the historical average of 1.6mm/yr. Interestingly, sea level rise is not even across the globe due to ocean circulation and mass. In a La Niña year, the Western Pacific Ocean can be 10-20cm higher than the average for the decade, but there’s only one way sea levels are going as the water warms and expands and the ice sheets melt – up.

Sea level rise (from report)

Sea level rise (from report)

Finally, if all of that wasn’t enough bad news for you – the report looked at the gas concentrations in the atmosphere and found (surprise, surprise) that CO2 is up and accounts for 64% of the increase in radiative forcing (making our planet warmer) over the past decade and 81% of the increase in the last five years. Methane is responsible for 18% of the increase and Nitrous Oxides chip in 6%.

Does it make anyone feel better if I tell you the hole in the ozone layer isn’t getting bigger anymore?

Basically the world we live in is getting more extreme as it heats up at an ever increasing rate. Given that these are the changes we’re seeing with a 0.8oC increase in global average temperatures and that’s from carbon we burnt over a decade ago, how about we stop burning carbon with a little more urgency now?

Greenland Whodunit

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“The next 5–10 years will reveal whether or not [the Greenland Ice Sheet melting of] 2012 was a one off/rare event resulting from the natural variability of the North Atlantic Oscillation or part of an emerging pattern of new extreme high melt years.”

WHO: Edward Hanna, Department of Geography, University of Sheffield, Sheffield, UK
 Xavier Fettweis, Laboratory of Climatology, Department of Geography, University of Liège, Belgium
Sebastian H. Mernild, Climate, Ocean and Sea Ice Modelling Group, Computational Physics and Methods, Los Alamos National Laboratory, USA, Glaciology and Climate Change Laboratory, Center for Scientific Studies/Centre de Estudios Cientificos (CECs), Valdivia, Chile
John Cappelen, Danish Meteorological Institute, Data and Climate, Copenhagen, Denmark
Mads H. Ribergaard, Centre for Ocean and Ice, Danish Meteorological Institute, Copenhagen, Denmark
Christopher A. Shuman, Joint Center for Earth Systems Technology, University of Maryland, Baltimore, USA,  Cryospheric Sciences Laboratory, NASA Goddard Space Flight Center, Greenbelt, USA
Konrad Steffen, Swiss Federal Research Institute WSL, Birmensdorf, Switzerland, Institute for Atmosphere and Climate, Swiss Federal Institute of Technology, Zürich, Switzerland, Architecture, Civil and Environmental Engineering, École Polytechnique Fédéral de Lausanne, Switzerland
 Len Wood, School of Marine Science and Engineering, University of Plymouth, Plymouth, UK
Thomas L. Mote, Department of Geography, University of Georgia, Athens, USA

WHAT: Trying to work out the cause of the unprecedented melting of the Greenland Ice Sheet in July 2012

WHEN: 14 June 2013

WHERE: International Journal of Climatology (Int. J. Climatol.) Vol. 33 Iss. 8, June 2013

TITLE: Atmospheric and oceanic climate forcing of the exceptional Greenland ice sheet surface melt in summer 2012 (subs req.)

Science can sometimes be like being a detective (although I would argue it’s cooler) – you’ve got to look at a problem and try and work out how it happened. These researchers set out to do exactly that to try and work out how the hell it was that 98.6% of the ice sheet on Greenland started melting last summer.

Greenland – July 8th on the left only half melting. July 12th on the right, almost all melting (Image: Nicolo E. DiGirolamo, SSAI/NASA GSFC, and Jesse Allen, NASA Earth Observatory)

Greenland – July 8th on the left only half melting. July 12th on the right, almost all melting (Image: Nicolo E. DiGirolamo, SSAI/NASA GSFC, and Jesse Allen, NASA Earth Observatory)

For a bit of context, Greenland is the kind of place where the average July temperature in the middle of summer is 2oC and the average summer temperature at the summit of the ice sheet is -13.5oC. Brrr – practically beach weather! So there’s got to be something weird going on for the ice sheet to start melting like that. Who are the suspects?

Atmospheric air conditions
Suspect number one is the atmospheric air conditions. The summer of 2012 was influenced strongly by ‘dominant anti-cyclonic conditions’ which is where warm southerly air moves north and results in warmer and drier conditions. There was also a highly negative North Atlantic Oscillation (NAO) which created high temperatures at high altitudes around 4km above sea level, which could explain the melting on the summit. The researchers also pointed out that the drier conditions meant less cloud cover and more sunny days, contributing to speedier melting.

There were issues with the polar jet stream that summer, where it got ‘blocked’ and stuck over Greenland for a while. The researchers used the Greenland Blocking Index (GBI), which while not trading on the NYSE, does tell you about wind height anomalies at certain geopotential heights (yeah, lots of meteorological words in this paper!). All of this makes the atmosphere look pretty guilty.

Jet stream getting funky – temperature anomaly patterns at 600 hectopascals pressure, aka 4000m above sea level with a big red blob over Greenland (from paper)

Jet stream getting funky – temperature anomaly patterns at 600 hectopascals pressure, aka 4000m above sea level with a big red blob over Greenland (from paper)

Sea surface temperatures
Suspect number two is sea surface temperatures. If it was warmer in the ocean – that could have created conditions where the ice sheet melted faster right? The researchers ran a simulation of the conditions around Greenland for the summer of 2012 and then played around with different temperature levels for sea surface, as well as levels of salinity. It didn’t make more than 1% difference, so they don’t think it was sea surface. Also, ocean temperatures change more slowly than air temperatures (that’s why the ocean is still so cold even in the middle of summer!) and when they looked at the data for sea surface temperature, it was actually a bit cooler in 2012 than it was in 2011. Not guilty sea surface temperatures.

Sea surface temperatures (top) and salinity (bottom) both decreasing (from paper)

Sea surface temperatures (top) and salinity (bottom) both decreasing (from paper)

Cloud patterns
Suspect number three is cloud cover patterns, which the researchers said could be a contributor to the ice sheet melting. However, they don’t have a detailed enough data set to work out how much clouds could have contributed to the melt. Not guilty for now clouds – due to lack of evidence.

Which leaves suspect number one – atmospheric air conditions. Guilty! Or, as the paper says ‘our present results strongly suggest that the main forcing of the extreme Greenland Ice Sheet surface melt in July 2012 was atmospheric, linked with changes in the summer NAO, GBI and polar jet stream’.

Now comes the scary part – it’s the atmosphere that we’ve been conducting an accidental experiment on over the last 200 years by burning fossil fuels. As the researchers point out, the North Atlantic Oscillation has a natural variability and patterns, so we could all cross our fingers and hope that the Greenland melting was a once off anomaly. Given the work that Dr Jennifer Francis has been doing at Rutgers into polar ice melt and how that slows the jet stream and causes it to meander; this may not be a good bet. Combine this with the fact that this level of melting is well beyond ‘the most pessimistic future projections’ and it’s getting scarier. This kind of melting was not supposed to occur until 2100, or 2050 in the worst case scenarios.

Interestingly, this could also link through to some of the work Jason Box is doing with his DarkSnow project in Greenland looking at how soot from fires and industry are affecting the melting of Greenland. The paper concludes that the next 5-10 years will show us whether it was a one off or the beginning of a new normal. Unless we stop burning carbon, it will only be the start of a terrifying new normal.

Crash Diets and Carbon Detoxes: Irreversible Climate Change

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Much of the changes humans are causing in our atmosphere today will be largely irreversible for the rest of the millennium.

WHO: Susan Solomon, Chemical Sciences Division, Earth System Research Laboratory, National Oceanic and Atmospheric Administration, Boulder, Colorado, USA
Gian-Kasper Plattner, Institute of Biogeochemistry and Pollutant Dynamics, Zurich, Switzerland
Reto Knutti, Institute for Atmospheric and Climate Science, Zurich, Switzerland,
Pierre Friedlingstein, Institut Pierre Simon Laplace/Laboratoire des Sciences du Climat et de  l’Environnement, Unité Mixte de Recherche à l’Energie Atomique – Centre National de la Recherche Scientifique–Université Versailles Saint-Quentin, Commissariat a l’Energie Atomique-Saclay, l’Orme des Merisiers, France

WHAT: Looking at the long term effects of climate pollution to the year 3000

WHEN: 10 February 2009

WHERE: Proceedings of the National Academy of Sciences of the USA (PNAS), vol. 106, no. 6 (2009)

TITLE: Irreversible climate change due to carbon dioxide emissions

Stopping climate change often involves the metaphor of ‘turning down the thermostat’ of the heater in your house; the heater gets left on too high for too long, you turn the thermostat back down, the room cools down, we are all happy.

This seems to also be the way many people think about climate change – we’ve put too much carbon pollution in the atmosphere for too long, so all we need to do is stop it, and the carbon dioxide will disappear like fog burning off in the morning.

Except it won’t. This paper, which is from 2009 but I came across it recently while reading around the internet, looks at the long term effects of climate change and found that for CO2 emissions, the effects can still be felt for 1,000 years after we stop polluting. Bummer. So much for that last minute carbon detox that politicians seem to be betting on. Turns out it won’t do much.

The researchers defined ‘irreversible’ in this paper at 1,000 years to just beyond the year 3000, because over a human life span, 1,000 years is more than 10 generations. Geologically, it’s not forever, but from our human point of view it pretty much is forever.

So what’s going to keep happening because we can’t give up fossil fuels today that your great-great-great-great-great-great-great-great-great-great grandkid is going to look back on and say ‘well that was stupid’?

The paper looked at the three most detailed and well known effects: atmospheric temperatures, precipitation patterns and sea level rise. Other long term impacts will be felt through Arctic sea ice melt, flooding and heavy rainfall, permafrost melt, hurricanes and the loss of glaciers and snowpack. However, the impacts with the most detailed models and greatest body of research were the ones chosen for this paper (which also excluded the potential for geo-engineering because it’s still very uncertain and unknown).

Our first problem is going to be temperature increases, because temperatures increase with increased CO2  accumulation in the atmosphere, but if we turned off emissions completely (which is unfeasible practically, but works best to model the long term effects) temperatures would remain constant within about 0.5oC until the year 3000.

Why does this occur? Why does the temperature not go back down just as quickly once we stop feeding it more CO2? Because CO2 stays in the atmosphere for a much longer time than other greenhouse gases. As the paper says: ‘current emissions of major non-carbon dioxide greenhouse gases such as methane or nitrous oxide are significant for climate change in the next few decades or century, but these gases do not persist over time in the same way as carbon dioxide.’

Temperature changes to the year 3000 with different CO2 concentration peaks (from paper)

Temperature changes to the year 3000 with different CO2 concentration peaks (from paper)

Our next problem is changing precipitation patterns, which can be described by the Clausius-Clapeyron law of the physics of phase transition in matter. What the law tells us is that as temperature increases, there is an increase in atmospheric water vapour, which changes how the vapour is transported through the atmosphere, changing the hydrological cycle.

The paper notes that these patterns are already happening consistent with the models for the Southwest of the USA and the Mediterranean. They found that dry seasons will become approx. 10% dryer for each degree of warming, and the Southwest of the USA is expected to be approx. 10% dryer with 2oC of global warming. As a comparison, the Dust Bowl of the 1930s was 10% dryer over two decades. Given that many climate scientists (and the World Bank) think that we’ve already reached the point where 2oC of warming is inevitable, it seems like Arizona is going to become a pretty uncomfortable place to live.

Additionally, if we managed to peak at 450ppm of CO2, irreversible decreases in precipitation of ~8-10% in the dry season would be expected in large areas of Europe, Western Australia and North America.

Dry season getting dryer around the world (from paper)

Dry season getting dryer around the world (from paper)

Finally, the paper looked at sea level rise, which is a triple-whammy. The first issue is that warming causes colder water to expand (aka thermal expansion) which increases sea level. The second is that ocean mixing through currents will continue, which will continue the warming and the thermal expansion. Thirdly, warming of icecaps on land contributes new volume to the ocean.

The paper estimates that the eventual sea level rise from thermal expansion of warming water is 20 – 60cm per degree of climate change. Additionally, the loss of glaciers and small icecaps will give us ~20 – 70cm of sea level rise too, so we’re looking at 40 – 130cm of sea level rise even before we start counting Greenland (which is melting faster than most estimates anyway).

Sea level rise from thermal expansion only with different CO2 concentration peaks (from paper)

Sea level rise from thermal expansion only with different CO2 concentration peaks (from paper)

What does all of this mean? Well firstly it means you should check how far above sea level your house is and you may want to hold off on that ski cabin with all the melting snowpack as well.

More importantly though, it means that any last minute ‘saves the day’ Hollywood-style plans for reversing climate change as the proverbial clock counts down to zero are misguided and wrong. The climate pollution that we are spewing into the atmosphere at ever greater rates today will continue to be a carbon hangover for humanity for the next 1000 years or so. Within human time scales, the changes that we are causing to our atmosphere are irreversible.

So naturally, we should stop burning carbon now.

Unprecedented: Melting Before Our Eyes

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The volume of Arctic sea ice is reducing faster than the area of sea ice, further speeding the arctic death spiral.

WHO:  Seymour W. Laxon, Katharine A. Giles, Andy L. Ridout, Duncan J. Wingham, Rosemary Willatt, Centre for Polar Observation and Modelling, Department of Earth Sciences, University College London, London, UK
Robert Cullen, Malcolm Davidson, European Space Agency, Noordwijk, The Netherlands
Ron Kwok, Jet Propulsion Laboratory, California Institute of Technology, Pasadena, California, USA.
Axel Schweiger, Jinlun Zhang, Polar Science Center, Applied Physics Laboratory, University of Washington, Seattle, Washington, USA
Christian Haas, Department of Earth and Space Science and Engineering, York University, Toronto, Canada.
Stefan Hendricks, Alfred Wegener Institute for Polar and Marine Research, Bremerhaven, Germany
Richard Krishfield, Woods Hole Oceanographic Institution, Woods Hole, Massachusetts, USA
Nathan Kurtz,School of Computer, Math, and Natural Sciences, Morgan State University, Baltimore, Maryland, USA.
Sinead Farrell, Earth System Science Interdisciplinary Center, University of Maryland, Maryland, USA.

WHAT: Measuring the volume of polar ice melt

WHEN: February 2013 (online pre-published version)

WHERE: American Geophysical Union, 2013, doi: 10.1002/grl.50193

TITLE:  CryoSat-2 estimates of Arctic sea ice thickness and volume (subs req.)

Much has been written about the Arctic Death Spiral of sea ice melting each spring and summer, with many researchers attempting to model and predict exactly how fast the sea ice is melting and when we will get the horrifying reality of an ice-free summer Arctic.

But is it just melting at the edges? Or is the thickness, and therefore the volume of sea ice being reduced as well? That’s what these researchers set out to try and find out using satellite data from CryoSat-2 (Science with satellites!).

The researchers used satellite radar altimeter measurements of sea ice thickness, and then compared their results with measured in-situ data as well as other Arctic sea ice models.

A loss of volume in Arctic sea ice is a signifier of changes in the heat exchange between the ice, ocean and atmosphere, and most global climate models predict a decrease in sea ice volume of 3.4% per decade which is larger than the predicted 2.4% per decade of sea ice area.

Sea ice area minimum from September 2012 (image: NASA/Goddard Space Flight Center Scientific Visualization Studio)

Sea ice area minimum from September 2012 (image: NASA/Goddard Space Flight Center Scientific Visualization Studio)

The researchers ran their numbers for ice volume in winter 2010/11 and winter 2011/12, and then used the recorded data sets to check the accuracy of their satellites (calibration for my fellow science nerds).

The most striking thing they found was a much greater loss of ice thickness in the north of Greenland and the Canadian Archipelago. Additionally, they found that the first year ice was thinner in autumn, which made it harder to catch up to average thickness during the winter, and made greater melting easier in summer.

Interestingly, they found that there was additional ice growth in winter between 2010-12 (7,500km3) compared to 2003-08 (5,000km3), which makes for an extra 36cm of ice growth in the winter. Unfortunately the increased summer melt is much greater than the extra growth, so it’s not adding to the overall thickness of the sea ice.

For the period of 2010-12 the satellite measured rate of decline in autumn sea ice was 60% greater than the predicted decline using PIOMAS (Panarctic Ice Ocean Modeling and Assimilation System). Most researchers when seeing results like that might hope that there’s an error, however when measured against the recorded data, the CryoSat-2 data was within 0.1 metres of accuracy. So while astounding, the 60% greater than expected loss of sea ice thickness is pretty spot on.

The researchers think that lower ice thickness at the end of winter in February and March could be contributing to the scarily low September minimums in the arctic death spiral, but the greatest risk here is that the ever increasing melt rate of ice in the arctic could take the climate beyond a tipping point where climate change is both irreversible and uncontrollable in a way we are unable to adapt to.

Visualisation of reduction in arctic sea ice thickness (from Andy Lee Robinson, via ClimateProgress)

Visualisation of reduction in arctic sea ice thickness (from Andy Lee Robinson, via ClimateProgress)

So as usual, my remedy for all of this is: stop burning carbon.

Sleepwalking off a Cliff: Can we Avoid Global Collapse?

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‘Without significant pressure from the public demanding action, we fear there is little chance of changing course fast enough to forestall disaster’
Drs. Paul and Anne Ehrlich

WHO: Paul R. Ehrlich, Anne H. Ehrlich, Department of Biology, Stanford University, California, USA

WHAT: An ‘invited perspective’ from the Royal Society of London for Improving Natural Knowledge (the Royal Society) on the future of humanity following the election of Dr. Paul Ehrlich to the fellowship of the Royal Society.

WHEN: 26 January 2013

WHERE: Proceedings of the Royal Society, Biological Sciences (Proc. R. Soc. B) 280, January 2013

TITLE: Can a collapse of global civilization be avoided?

Dr. Paul Ehrlich has been warning humanity about the dangers of exceeding the planet’s carrying capacity for decades. He first wrote about the dangers of over-population in his 1968 book The Population Bomb, and now following his appointment to the fellowship of the Royal Society, he and his wife have written what I can only describe as a broad and sweeping essay on the challenges that currently face humanity (which you should all click the link and read as well).

When you think about it, we’re living in a very unique period of time. We are at the beginning of the next mass extinction on this planet, which is something that only happens every couple of hundred million years. And since humans are the driving force of this extinction, we are also in control of how far we let it go. So the question is, will we save ourselves, or will we sleepwalk off the cliff?

Drs. Ehrlich describe the multiple pressures currently facing the planet and its inhabitants as a perfect storm of challenges. Not only is there the overarching threat multiplier of climate change, which will make all of our existing problems harder to deal with, we have concurrent challenges facing us through the loss of ecosystem services and biodiversity from mass extinction, land degradation, the global spread of toxic chemicals, ocean acidification, infectious diseases and antibiotic resistance, resource depletion (especially ground water) and subsequent resource conflicts.

you have humans Wow. That’s quite the laundry list of problems we’ve got. Of course, all these issues interact not only with the biosphere; they interact with human socio-economic systems, including overpopulation, overconsumption and current unequal global economic system.

If you haven’t heard the term ‘carrying capacity’ before, it’s the limit any system has before things start going wrong – for instance if you put 10 people in a 4 person hot tub, it will start to overflow, because you’ve exceeded its carrying capacity.

The bad news is we’ve exceeded the planet’s carrying capacity. For the planet to sustainably house the current 7 billion people it has, we would need an extra half an empty planet to provide for everyone. If we wanted all 7 billion of us to over-consume at the living standards of the USA, we would need between 4 – 5 extra empty planets to provide for everyone. Better get searching NASA!

The Andromeda Galaxy (photo: ESA/NASA/JPL-Caltech/NHSC)

The Andromeda Galaxy (photo: ESA/NASA/JPL-Caltech/NHSC)

The next problem is that a global collapse could be triggered by any one of the above issues, with cascading effects, although Drs. Ehrlich think the biggest key will be feeding everyone (which I’ve written about before), because the social unrest triggered by mass famine would make dealing with all the other problems almost impossible.

So what do we need to do? We need to restructure our energy sources and remove fossil fuel use from agriculture, although Drs. Ehrlich do point out that peaking fossil fuel use by 2020 and halving it by 2050 will be difficult. There’s also the issue that it’s really ethically difficult to knowingly continue to run a lethal yet profitable business, hence the highly funded climate denial campaigns to try and keep the party running for Big Oil a little longer, which will get in the way of change.

The global spread of toxic compounds can only be managed and minimised as best we can, similarly, we don’t have many answers for the spread of infectious and tropical diseases along with increasing antibiotic resistance that will happen with climate change.

Helpfully, Drs. Ehrlich point out that the fastest way to cause a global collapse would be to have any kind of nuclear conflict, even one they refer to as a ‘regional conflict’ like India and Pakistan. But even without nuclear warfare (which I hope is unlikely!) 6 metres of sea level rise would displace around 400 million people.

One of the most important things that we can be doing right now to help humanity survive for a bit longer on this planet is population control. We need less people on this planet (and not just because I dislike screaming children in cafes and on airplanes), and Drs. Ehrlich think that instead of asking ‘how can we feed 9.6 billion people in 2050’ scientists should be asking ‘how can we humanely make sure it’s only 8.6 billion people in 2050’?

How can we do that? Firstly, we need to push back against what they refer to as the ‘endarkenment’, which is the rise of religious fundamentalism that rejects enlightenment ideas like freedom of thought, democracy, separation of church and state, and basing beliefs on empirical evidence, which leads to climate change denialism, failure to act on biodiversity loss and opposition to the use of contraceptives.

And why do we need to push back against people who refuse to base their beliefs on empirical evidence? Because the fastest and easiest way to control population growth is female emancipation. Drs. Ehrlich point out that giving women everywhere full rights, education and opportunities as well as giving everyone on the planet access to safe contraception and abortion is the best way to control population growth (you know, letting people choose whether they’d like children).

More importantly, Drs. Ehrlich want the world to develop a new way of thinking systematically about things, which they’ve called ‘foresight intelligence’. Since it’s rare that societies manage to mobilise around slow threats rather than immediate threats, there need to be new ways and mechanisms for greater cooperation between people, because we are not going to succeed as a species if we don’t work together.

They’d like to see the development of steady-state economics which would destroy the ‘fables such as ‘technological innovation will save us’’. They’d like to see natural scientists working together with social scientists to look at the dynamics of social movements, sustainability and equality and to scale up the places where that kind of work is already happening.

They point out that our current methods of governance are inadequate to meet the challenges we face and that we need to work with developing nations who are currently looking to reproduce the western nation’s ‘success’ of industrialisation, so that they can instead be leaders to the new economy, because playing catch up will lead to global collapse.

Do Drs. Ehrlich believe that we can avoid a global collapse of civilisation? They think we still can, but only if we get fully into gear and work together now, because unless we restructure our way of doing things, nature will do it for us. It’s your call humanity – shall we get going, or will we sleepwalk our species off the cliff?

Will the Well Run Dry? Non-renewable Water

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Ancient groundwater sources are being depleted at fast rates and the impacts of climate change are still unknown

WHO: Richard G. Taylor, Department of Geography, University College London, London, UK
Bridget Scanlon, Bureau of Economic Geology, Jackson School of Geosciences, University of Texas at Austin, Texas, USA
Petra Döll, Institute of Physical Geography, University of Frankfurt, Frankfurt, Germany
Matt Rodell, Hydrological Science Branch, NASA Goddard Space Flight Center, Greenbelt, Maryland, USA
Rens van Beek, Yoshihide Wada, Marc F. P. Bierkens, Department of Physical Geography, University of Utrecht, Utrecht, The Netherlands
Laurent Longuevergne, Géosciences Rennes, Université de Rennes 1, Rennes, France
Marc Leblanc, School of Earth and Environmental Sciences, NCGRT, James Cook University, Cairns QLD, Australia
James S. Famiglietti, UC Center for Hydrologic Modelling, University of California, Irvine, USA
Mike Edmunds, School of Geography and the Environment, Oxford University, Oxford, UK
Leonard Konikow, U.S. Geological Survey, Reston, Virginia, USA
Timothy R. Green, Agricultural Systems Research Unit, USDA-ARS, Fort Collins, Colorado, USA
Jianyao Chen, School of Geography and Planning, Sun Yat-sen University, Guangzhou, China
Makoto Taniguchi, Research Institute for Humanity and Nature, Kyoto, Japan
Alan MacDonald, British Geological Survey, Edinburgh, UK
Ying Fan, Department of Earth and Planetary Sciences, Rutgers University, New Jersey, USA
Reed M. Maxwell, Department of Geology and Geological Engineering, Colorado School of Mines, Golden, Colorado, USA
Yossi Yechieli, Geological Survey of Israel, Jerusalem, Israel
Jason J. Gurdak, Department of Geosciences, San Francisco State University, San Francisco, California, USA
Diana M. Allen, Department of Earth Sciences, Simon Fraser University, Burnaby, British Columbia, Canada
Mohammad Shamsudduha, Institute for Risk and Disaster Reduction, University College London, London, UK
Kevin Hiscock, School of Environmental Sciences, University of East Anglia, Norwich Research Park, Norwich, UK
Pat J.-F. Yeh, International Centre for Water Hazard and Risk Management (ICHARM), UNESCO, Tsukuba, Japan
Ian Holman, Environmental Science and Technology Department, Cranfield University, Milton Keynes, UK
Holger Treidel, Division of Water Sciences, UNESCO-IHP, Paris, France

WHAT: Looking at all the research on groundwater and working out what we know and what we don’t know

WHEN: 25 November, 2012

WHERE: Nature Climate Change, 2012 nclimate1744

TITLE: Ground water and climate change (subs req.)

Last month, 26 scientists all published a paper together on groundwater, which must have required either some massive Skype sessions, or people getting very sick of email chains where everyone hits ‘reply all’. As I’ve said before: science – it’s a collaborative thing.

What these researchers were trying to do was to work out exactly what we know about groundwater and how it will be affected by climate change and where the gaps are that we need to fill. Having worked in water policy, I can tell you that groundwater is normally the big unknown. Governments and organisations generally don’t have the information to know how much there is, who is taking it at what rates and how to monitor and regulate it. Generally, it gets put off until next time, while surface water rights are dealt with.

However, groundwater is estimated to be one third of all freshwater withdrawals worldwide and also the water source for 42% of the world’s agricultural water. So with climate change affecting rain patterns and shifting weather pole-ward, what will happen to groundwater? Will the well run dry in some places?

One of the biggest issues with measuring groundwater is the rate of recharge for the underground aquifers. These underwater storage vaults of water and mostly ancient water in that if you measure the isotopic composition of the water, they were likely filled thousands of years ago and have remained there without changing greatly.

Another interesting thing the isotopic analysis of the water tells us, is that if you look at the oxygen and hydrogen isotope ratios (so that’s the ratio of atoms that have different numbers of neutrons, making some heavier than others), many aquifers were filled in the late Pleistocene and early Holocene eras, around 12,000 years ago when the average temperature of the earth was around 5oC cooler than now.

Isotopic analysis: Hydrogen on the left and it’s isotope Deuterium (with the extra neutron) on the right

Isotopic analysis: Hydrogen on the left and it’s isotope Deuterium (with the extra neutron) on the right

What that means is that if those aquifers were recharging when the world was 5oC cooler than now, it’s unlikely that any recharge is taking place now or going to take place as we continue to heat our world through climate change. As the paper says ‘this non-renewable groundwater exploitation is unsustainable and is mined in a manner similar to oil’. Thousand year old water is just as renewable as million year old oil, and both are longer than a human life span.

So, what do we know about groundwater? There are two ways that groundwater can recharge: rain fed (the rain soaks into the ground) and surface water leakage (from rivers, irrigated agriculture or lakes). Both of these methods will be variable and vulnerable to climate change.

Changes in snow pack and snow distribution also impact recharge. The research currently published is still uncertain as to the extent of the impacts, but early findings are that the early start to spring is reducing the duration of recharge. Glacial retreat also impacts groundwater.

The other affects on groundwater are land use change and sea level rise inundating areas and making them salty. Managed ecosystems are not able to respond to change the way natural ecosystems can. Even if it’s a drought year, a farmer still needs to plant and crop their land. For each degree of climate change, you can roughly estimate that the equivalent climate will move 150km towards the pole. The desert of Salt Lake City will move north into the cropping areas of Idaho, and the slushy snow will move north into the ‘champagne powder’ ski regions.

More importantly, global estimates of groundwater depletion by 2050 range from 70% decreases in the Mediterranean and Brazil to increases in the Middle East and only 10% decreases in the Western US. There’s lots of uncertainty in the models as there’s a lack of data, so researchers need to extrapolate from incomplete data, resulting in large uncertainty margins.

One interesting thing I learned from this paper that I hadn’t considered before is that groundwater depletion increases sea level rise. How, you may ask? It’s the thing of living in a planetary system where everything is connected, so follow me through the water cycle here:

Thousand year old water that has been stored in the ground is pumped up a well and onto your farm. Some of the water will evaporate and the other water will grow plants, but the water has now gone into the atmospheric water cycle, so the evaporated water goes into the clouds, comes down as rain, and since 70% of our planet is ocean, there’s a really high chance the ancient groundwater will get added to the ocean. How much water? This is where it gets scary.

Groundwater water cycles (from paper)

Groundwater water cycles (from paper)

The paper talks about cubic kilometres of water. Yes, kilometres. I was unable to mentally picture that too, so I did a conversion for you. The groundwater depletion for the planet is between 145 – 204km3 of water per year, which is between 145,000 and 204,000 billion litres of water. To visualise this, you’d need to take the island of Manhattan and cover it twice with 1km deep water, which would be a depth of 4.5 Empire State Buildings end to end. This contributes between 0.4-0.5mm of sea level rise each year.

Climate change will have an effect on groundwater resources. Exactly what that is won’t be known until all the data is collected to create detailed models. However, sustainable aquifer management is going to be difficult and grow increasingly difficult as the climate continues to change.

World Bank Wants off the Highway to Hell: Part Two

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‘Given that it remains uncertain whether adaptation and further progress toward development goals will be possible at this level of climate change, the projected 4°C warming simply must not be allowed to occur’ World Bank report

WHO: The Potsdam Institute for Climate Impact Research and Climate Analytics, commissioned by the World Bank

WHAT: A report looking at the impacts of 4oC of global warming and the risk to human systems

WHEN: November 2012

WHERE: The World Bank’s website

TITLE: Turn down the heat: Why a 4oC warmer world must be avoided

This is part two; part one is here.

What does a 4oC world look like?

It looks like a place where climate change has undermined economic growth through natural disaster after natural disaster which eventually overwhelms emergency response capabilities.

It looks like a world where all of the gains towards to the Millennium Development Goals of eradicating poverty and hunger have been wiped out by the negative impacts of climate change, and extreme heat stress has caused a 60% or more reduction in crop yield.

It looks like a world where even wealthy industrialised countries are no longer able to adapt to or meet development goals because of climate change and where entire coastal cities have been abandoned because the cost of fortifying them against rising sea levels was too great.

New York City in a 4oC world?
(Photo from New York Times Sunday Review Nov. 25th 2012 via ClimateProgress)

How could this happen? How could the change from 2oC to 4oC be the difference between continuing economic growth in a green economy and abandoned flooded cities?

Non-linear and cascading impacts.

Cast your minds back with me to high school math where you learned about exponential graphs. The ones that were y=x2 and you had to solve for x in your exams and it hurt your brain? This is non-linear and what is likely to happen with the planet. Take the oceans for example. While we still have sea ice in the Arctic, the warming from the oceans sucking up almost half of our carbon emissions every year is still relatively slow. However, once the ice melts and it’s all open water for the first time, that’s when warming gets going and it will likely ramp up like an exponential graph.

In fact, if you really feel like nerding it up, you can simulate sea ice at home and watch the tipping point happen. Put ice and water into a pot and once it’s cold (1-2oC) turn the heat on high and take the temperature every 30 seconds until the ice is all gone and the water is getting hotter (15-20oC or longer if you want). Graph the results and find your tipping point. Science!

Simulating Arctic ice melt: science! (photo: ©Adam Hart-Davis)

The final chapter in the World Bank report looks at the potential implications for a 4oC world in terms of risk management. If it’s going to cost a certain number of trillion dollars to prepare for 2oC, should we just double the amount and prepare for 4oC? They think that may not be enough since ‘lurking in the tails of the probability distributions are likely to be many unpleasant surprises’.

The report points out that since cascading effects are very difficult to predict, that most of the predictions I covered in part one are based on linear models and likely to be conservative estimates of what will happen with 4oC warming. They are also sector based and don’t take into account what happens when impacts team up and work together.

Going back to the oceans again, what will the cumulative impacts be of all the effects that have been studied separately? What happens when coral reefs collapse, marine production reduces from rising temperatures and acidification, low-lying coastal areas are inundated from sea level rise, and human economic and social impacts are all lumped together at the same time?

The report states that there is a high level of concern that all of those effects all happening together at once hasn’t really been studied or quantified beyond ‘horrifying’.

From what we know now from all of the leading research, this is a list of potential tipping points from the report:

1.5oC
This may be the coral reef tipping point which will create larger storm surges for coastal areas that were previously protected. It also means an economically significant loss of tourism dollars for places like the Great Barrier Reef.
This could also be the tipping point for the Greenland Ice Sheet which has been melting faster than expected (was previously predicted for 4.6oC). There is approximately 6-7m of sea level rise in this ice sheet, so New York City may need to move inland.

3oC
This could be the tipping point for the Amazon Rainforest, where large parts of the rainforest die off from lack of water and release more carbon into the atmosphere, further fuelling climate change in a positive feedback loop that it will be almost impossible to recover from.
This could also be the point for the West Antarctic Ice Sheet which has 3m of additional sea level rise stored in it. New York City will need to keep moving.

4oC
This is the probable tipping point for world agriculture as crops start dying from heat stress. The IPCC assessment predicts that crop yields will decrease between 63-82%. Keep in mind that this goes hand in hand with a population increase to 9 billion people.
This is also the point at which the accumulated stresses from 2oC and 3oC overwhelms emergency and health services and all of the gains made to alleviate poverty are also overwhelmed by the negative consequences from climate change.

Once the World Bank has laid out for us exactly how horrible it could possibly get in a way we can’t easily predict, plan for, adapt to safely or afford, this is the very simple conclusion they have that we should all be able to agree with:

‘Given that it remains uncertain whether adaptation and further progress toward development goals will be possible at this level of climate change, the projected 4°C warming simply must not be allowed to occur—the heat must be turned down. Only early, cooperative, international actions can make that happen.’

World Bank Wants off the Highway to Hell

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“It is my hope that this report shocks us into action… This report spells out what the world would be like if it warmed by 4 degrees Celsius… The 4oC scenarios are devastating.” Dr. Jim Yong Kim President, World Bank

WHO: The Potsdam Institute for Climate Impact Research and Climate Analytics, commissioned by the World Bank

WHAT: A report looking at the impacts of 4oC of global warming and the risk to human systems

WHEN: November 2012

WHERE: The World Bank’s website

TITLE: Turn down the heat: Why a 4oC warmer world must be avoided

Following on from last week’s Highway to Hell post, the World Bank released a report looking at the human system implications for climate change because things that disturb the current systems of running the world tend to be expensive for organisations like the World Bank.

The report looks at climate change projections for a 4oC world, most of which I’ve already covered on this blog like; ocean acidification, droughts, tropical cyclones, sea level rise and extreme temperatures. So I’m going to skip ahead to the chapters on impacts in different sectors and then my personal favourite, non-linear impacts. This week will be sector impacts.

It’s refreshing to see an organisation that is normally known for its staid and stuffy conservatism talking about climate change reality. The foreword by the World Bank’s President says no less than that the science is unequivocal, that warming of 4oC threatens our ability to adapt and that meeting the currently agreed upon UNFCCC targets (which we’re not meeting) will lead to 3.5-4oC warming which must be avoided through greater and more urgent action now.

Let’s look at what this bastion of the three piece suit with not a dreadlock in sight says about the impacts that could be felt in a 4oC world.

Agriculture
Generally the impacts for agriculture will be regionally specific, as will the impacts for climate change. Some regions will get more rain, some less rain, and the timing of the seasons will change.

The favourite argument of luke-warmists is that increased CO2 in the atmosphere is excellent because it will benefit agricultural growth and we’ll be able to grow lettuce in Siberia. Well, yes and no – it’s more complex than that. Between 1-3oC of warming it’s likely we’ll see increased yields in certain regions from CO2 fertilization. Beyond 3oC productivity will decrease as the stresses of other climate change impacts outweigh any benefit from extra CO2.

And even then, demand from a world population growing to a projected 9 billion by 2050 is going to increase demand by 70-100% for agricultural food products, so even without the costs of climate change reducing the productivity of crops, it’s going to be difficult to feed the world with that many people.

Another vulnerability for agriculture is sea level rise and salination of some of the world’s most productive agricultural land. Having to move your farm from a nutrient rich delta to less productive soil further inland will detrimentally affect crop yields.

Finally, the benefits of CO2 fertilisation will be limited by the availability of other nutrients. You can give a plant all the CO2 it wants, but if you don’t also give it nitrogen, phosphorus and water, it’s not going to grow any faster. It’s currently looking like there’s going to be a world shortage of phosphorus based fertilizer, which will have a very detrimental affect on world crops that need to be becoming more productive to feed a growing population, not less.

Water Resources
This section starts with a very obvious statement that is useful to point out: ‘The associated changes in the terrestrial water cycle are likely to affect the nature and availability of natural water resources and, consequently, human societies that rely on them.’

We rely on the services that the environment provides for us and the second most important one of these is water (the first one is air).

As well as the expected (and already occurring) more severe droughts, river runoff is expected to decrease significantly in areas where the water is used for both agriculture and transport like the Danube, the Mississippi, the Amazon and the Murray-Darling Basin in Australia.

In a 2oC warming world, most of the water stresses can be expected to be from population increase. By the time we get to a 4oC world, the stress of climate change will outstrip that of population increase. Even in the areas where there will be increased rainfall, it’s not likely to come at the right time of the year, or it could come all at once causing flooding.

There’s a lot of uncertainty in many models of drought prediction and rainfall prediction as well as the possible effects for specific regional areas, but the conclusions that are coming from all of the studies identified in this report range from bad to very bad, and in a 4oC world almost half of the world’s population could be water stressed by 2080.

Ecosystems and Biodiversity
This is the fun section that starts using terms like ‘mass extinction’ and gets everyone Googling things like the Eocene.

Biodiversity is, in my opinion going to be the ‘sleeper issue’ of climate change, because it happens over longer periods of time and is easy to ignore as out of sight out of mind for us urbanites until it’s too late. As the report quotes; ‘It is well established that loss or degradation of ecosystem services occurs as a consequence of species extinctions’.

There’s also the issue of thresholds. Where an animal or plant or ecosystem can absorb a certain amount of degradation, until you reach the tipping point and it can no longer take it. Some areas will be able to absorb more warming (Canada, Northern Europe) while others may reach biodiversity and ecosystem tipping points earlier (Pacific Islands, Bangladesh).

In a 4oC world, it’s possible that habitats could shift by up to 400km towards the poles, which is fine if you’re a mosquito moving north from Mexico, but not so good if you’re a mountain rabbit and you run out of mountain.

And here’s some food for thought: the report states that if the planet lost all of the species that are currently listed as ‘critically endangered’ we would officially be living through a mass extinction, and if we lost the species that are also ‘endangered’ or ‘vulnerable’ we would be confirmed as the sixth mass extinction in geological history. Which means history would list the dinosaurs and then the humans in the fossil record of mass extinctions.

As the report says: ‘loss of biodiversity will challenge those reliant on ecosystem services’. This means all of us.

Human Health
Like smoking, climate change is bad for your health. The above mentioned agricultural and water issues with a 4oC warmer world will lead to famine and malnutrition on a large scale. The extreme weather events from a planet on climate steroids will kill people in heat waves, increase respiratory diseases and allergies from the extra dust in the droughts, weaken existing health services through damage to hospitals in extreme storms, flooding and so on.

Living with constant extreme weather is bad for your mental health, whether it’s the slow and painful crush of watching drought destroy your farmland or the fast emergency of cyclones, hurricanes and floods.

And remember the mosquitoes moving north? They’ll bring new tropical diseases with them that will infect many new people who have never developed any immunity to them.

Given all of the above, it’s pretty clear why the World Bank wants off the highway to hell. Because they’re concerned about both loaning money to countries that are dealing with these catastrophes, and living through these impacts. Because, as all of my fellow Gen Ys already know, living these impacts by 2050 is not some vague and distant future. It’s before we all retire.

 

Next week: non-linear impacts, which are scarier than they sound. 

It’s Getting Hot in Here: A Brief History of Antarctic Warming

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The melting and re-freezing of Antarctic ice sheets has always happened on a millennium time-scale. This time, we’re doing it in decades…

WHO: Robert Mulvaney, Richard C. A. Hindmarsh, Louise Fleet, Jack Triest, Louise C. Sime, Susan Foord (British Antarctic Survey, Natural Environment Research Council, Cambridge, UK)
Nerilie J. Abram (British Antarctic Survey, Natural Environment Research Council, Cambridge, UK and Research School of Earth Sciences, The Australian National University, Canberra, Australia)
Carol Arrowsmith (NERC Isotope Geosciences Laboratory, Keyworth, UK)
Olivier Alemany (Laboratoire de Glaciologie et Geophysique de l’Environnement (LGGE), Grenoble, France)

WHAT: Taking a giant (363.9m) ice core sample in Antarctica to look at climate history

WHEN: 6 September 2012

WHERE: Nature 489, September 2012

TITLE: Recent Antarctic Peninsula warming relative to Holocene climate and ice-shelf history (subs. required)

There’s been a lot of press recently about the Arctic Death Spiral which is of great concern to the stability of our climate, and means the poor southern cousin of the Arctic – the Antarctic doesn’t get much of a look in. No Santa, not as much media, what’s even happening with those penguins down south?

Penguin! (KK Condon, flickr)

Well, it’s melting too, which is unsurprising given that the whole planet is heating up, but this group of British, Australian and French researchers have put together a short (~50,000 years) history of ice melt and temperature changes from their ice core. (How did the researchers know I did history AND science?!)

They drilled an ice core on James Ross Island that is 363.9m long (which gives a bit of perspective as to how much ice is in the Antarctic if it’s 363.9m deep!) and looked at the ratio of isotopes to work out what the climate and temperature was like. Isotopes are elements that are the same but have a different weight because of an extra neutron (the bits in an atom that have a neutral charge). Different isotopes occur naturally at different amounts – for instance, Carbon with a weight of 12 is the most common on earth and Carbon 13 (one neutron heavier) is found 1% of the time. This research looked at Hydrogen vs Deuterium isotopes.

James Ross Island, Antarctica (from paper)

Different isotope ratios can tell us what was and is going on in the atmosphere and 363.9m of ice core can tell us approx. 50,000 worth of history (the paper uses BP = before present. For some strange reason ‘present’ time is 1950, but then I guess BC and AD are just as arbitrary).

50,000 years BP was the last glacial interval before the Holocene, the current geological period we live in (although there’s an argument that we’re now living in the Anthropocene), all of which is in the ice core. There was a glacial maximum (26,000 – 20,000 years BP) which was 6.1C colder on James Ross Island than present and an early climactic optimum (warmest part) of the Holocene which was 1.3C warmer than present. Marine sediment samples show the ocean was 3.5C warmer.

Sustained warming on James Ross Island started occurring around 600 BP (1450AD for us) with a rate of .22C of warming per century. This cranked up with rapid warming between 1518 – 1621 and 1671 – 1777 of more than 1.25C.

The warming over the past 100 years has been the fastest warming seen in 2000 years, but it’s not yet out of the range of normal warming and cooling patterns for the Antarctic. However, the most recent phase of warming started in the 1920s (so will be more influenced by industrial and human pollution than the earlier warming) and it’s going at a rate of 2.6C per century. Which is double the rate of the natural warming above.

What does faster warming mean for Antarctic ice sheets? The rapid warming means the ice becomes unstable, and the researchers say that continued warming at the pace currently being observed could lead to an ice sheet collapsing. Additionally, if the warming continues, it will start melting the southern ice sheets that were stable in the earlier Holocene warm period.

So why should we, sitting at our computers a long way from the Antarctic care about melting ice sheets? Well other than the huge inconvenience that’s going to be for a whole range of cute animals like penguins whales and seals, melting ice sheets on land cause sea level to rise. The melting of the Arctic is certainly of concern for Northern Hemisphere weather patterns, but the melting of floating ice, doesn’t change sea level.

The melting of ice that is on an island does raise the sea level. And the melting of the entire Antarctic ice sheet would contribute an extra 60m to sea level. Which is horrifying, and a really good reason to care about the speed of melting in Antarctica. That kind of rise puts my hometown of Melbourne totally underwater (elevation 31m). It puts half of Vancouver underwater (elevation 0 – 152m) and all of London as well (elevation 24m).

Now, obviously the total melting of the Antarctic ice sheet is going to take a long time given how large it is. However, it’s really difficult to stop once started. And given that I keep talking about how climate change is going to be non-linear and unpredictable when feedbacks unexpectedly kick in from tipping points, I’d argue we shouldn’t be playing Russian roulette with this one and we should stop burning carbon instead.

[EDITED 21 Sept. to reflect the note from the lead author of the paper that an ice sheet is on land and an ice shelf is floating in water – AH]