Greenland Whodunit

“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.

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Much ado about phosphorus

‘Life can multiply until all the phosphorus has gone and then there is an inexorable halt which nothing can prevent’ – Isaac Asimov, 1974

WHO: K. Ashley, D. Mavinic, Department of Civil Engineering, Faculty of Applied Science, University of British Columbia, Vancouver, BC, Canada
D. Cordell, Institute for Sustainable Futures, University of Technology, Sydney, Australia

WHAT: A brief history of phosphorus use by humans and ideas on how we can prevent the global food security risk of ‘Peak Phosphorus’

WHEN: 8 April 2011

WHERE: Chemosphere Vol. 84 (2011) 737–746

TITLE: A brief history of phosphorus: From the philosopher’s stone to nutrient recovery and reuse (subs req.)

Phosphorus can be found on the right hand side of your periodic table on the second row down underneath Nitrogen. It’s one of those funny elements that we all need to live and survive and grow things, but is also highly reactive, very explosive and toxic.

It’s in our DNA – in the AGCT bases that connect to form the double helix structure of DNA, the sides of the ladder are held together by phosphodiester bonds. Phosphorus is literally helping to hold us together.

Phosphodiester bonds in DNA (from Introduction to DNA structure, Richard B. Hallick, U Arizona)

Phosphodiester bonds in DNA (from Introduction to DNA structure, Richard B. Hallick, U Arizona)

Phosphorus can be pretty easily extracted from human urine, which was what German alchemist Henning Brandt did in the 1660s in an attempt to create the Philosopher’s Stone which would be able to turn base metals into gold. No seriously, apparently he was committed enough to the idea to distill 50 buckets of his own pee to do this!

What do alchemy, DNA, and human pee have to do with a scientific paper? Well these researchers were looking at how we’ve previously used phosphorus, why it is that we’re now running out of it and what we can learn from history to try and avoid a global food security risk.

Phosphorus comes in three forms – white, black and red. The phosphorus that is mined for fertilizer today is apatite rock containing P2O5 and has generally taken 10 – 15million years to form. However, in traditional short term human thinking, the fact that it takes that long for the rocks to form didn’t stop people from mining it and thinking it was an ‘endless’ resource (just like oil, coal, forests, oceans etc.).

The paper states that originally, phosphorus was used for ‘highly questionable medicinal purposes’ and then doesn’t detail what kinds of whacky things it was used for (boo!). Given the properties of white phosphorus; it’s highly reactive and flammable when exposed to the air, can spontaneously combust and is poisonous to humans, the mind boggles as to what ‘medicinal’ uses phosphorus had.

The major use of phosphorus is as an agricultural fertilizer, which used to be achieved through the recycling of human waste and sewage pre-industrialisation. However, with 2.5million people living in Victorian-era London, the problems of excess human waste become unmanageable and led to all kinds of nasty things like cholera and the ‘Great Stink’ of the Thames in 1858 that was so bad that it shut down Parliament.

This led to what was called the ‘Sanitary Revolution’ aka the invention of flush toilets and plumbing on a large scale. This fundamentally changed the phosphorus cycle – from a closed loop of localised use and reuse to a more linear system as the waste was taken further away.

After the Second World War, the use of mined mineral phosphorus really took off – the use of phosphorus as a fertilizer rose six fold between 1950-2000 – and modern agricultural processes are now dependent on phosphorus based fertilizers. This has led to major phosphorus leakage into waterways and oceans from agricultural runoff creating eutrophication and ocean deadzones from excess phosphorus.

Eutrophication in the sea of Azov, south of the Ukraine  (SeaWiFS Project, NASA/Goddard Space Flight Center, and ORBIMAGE)

Eutrophication in the sea of Azov, south of the Ukraine
(SeaWiFS Project, NASA/Goddard Space Flight Center, and ORBIMAGE)

The problem here is, that we’ve switched from a closed loop system where the waste from the farm house goes into the farm yard and all the phosphorus can recycle, to a linear system where the phosphorus gets mined, used as fertilizer and much of it runs off into the ocean. It’s not even a very efficient system – only a fifth of the phosphorus mined for food production actually ends up in the food we eat.

The problem that we’re now facing is the long term ramifications of this new system where phosphorus has become a scarce global resource and we’ve now been forced to start mining the rocks that have lower quality phosphorus with higher rates of contaminants and are more difficult to access. We’re down to the tar sands equivalent of minable phosphorus, most of which is found in only five countries; Morocco, China, the USA, Jordan and South Africa. Maybe they can be the next OPEC cartel for phosphorus?

Peak phosphorus is likely to happen somewhere between 2030 and 2040, which is where the scary link to climate change comes in. The researchers cheerfully call phosphorus shortages the ‘companion show-stopper to climate change’, by which they mean that soils will start to run out of the nutrients they need at about the same time that extended droughts from climate change will be diminishing crop yields and we’ll have about 9 billion people to scramble to feed.

Basically, a phosphorus shortage is something that we can easily avoid through better and more efficient nutrient recycling, but it’s something that will kick us in the ass once we’re already struggling to deal with the consequences of climate change. The paper states that we need to start re-thinking our ‘western style’ of sewage treatment to better recover water, heat, energy, carbon, nitrogen and phosphorus from our waste systems. This doesn’t mean (thankfully) having to return to a middle ages style of living – it means having cities that are innovative enough about their municipal systems (I was surprised to find out that sewage treatment is one of the most expensive and energy intensive parts of public infrastructure).

The False Creek Neighbourhood Energy Utility in Vancouver

The False Creek Neighbourhood Energy Utility in Vancouver

In Vancouver, we’re already starting to do that with the waste cogeneration system at Science World and the False Creek Neighbourhood Energy Utility that produces energy from sewer heat.

It’s pretty logical; we need to re-close the loop on phosphorus use and we need to do it sensibly before our failure to stop burning carbon means ‘Peak Phosphorus’ becomes the straw that breaks the camel’s proverbial back.

Pandora’s Permafrost Freezer

What we know about permafrost melt is less than what we don’t know about it. So how do we determine the permafrost contribution to climate change?

WHO: E. A. G. Schuur, S. M. Natali, C. Schädel, University of Florida, Gainesville, FL, USA
B. W. Abbott, F. S. Chapin III, G. Grosse, J. B. Jones, C. L. Ping, V. E. Romanovsky, K. M. Walter Anthony University of Alaska Fairbanks, Fairbanks, AK, USA
W. B. Bowden, University of Vermont, Burlington, VT, USA
V. Brovkin, T. Kleinen, Max Planck Institute for Meteorology, Hamburg, Germany
P. Camill, Bowdoin College, Brunswick, ME, USA
J. G. Canadell, Global Carbon Project CSIRO Marine and Atmospheric Research, Canberra, Australia
J. P. Chanton, Florida State University, Tallahassee, FL, USA
T. R. Christensen, Lund University, Lund, Sweden
P. Ciais, LSCE, CEA-CNRS-UVSQ, Gif-sur-Yvette, France
B. T. Crosby, Idaho State University, Pocatello, ID, USA
C. I. Czimczik, University of California, Irvine, CA, USA
J. Harden, US Geological Survey, Menlo Park, CA, USA
D. J. Hayes, M. P.Waldrop, Oak Ridge National Laboratory, Oak Ridge, TN, USA
G. Hugelius, P. Kuhry, A. B. K. Sannel, Stockholm University, Stockholm, Sweden
J. D. Jastrow, Argonne National Laboratory, Argonne, IL, USA
C. D. Koven, W. J. Riley, Z. M. Subin, Lawrence Berkeley National Lab, Berkeley, CA, USA
G. Krinner, CNRS/UJF-Grenoble 1, LGGE, Grenoble, France
D. M. Lawrence, National Center for Atmospheric Research, Boulder, CO, USA
A. D. McGuire, U.S. Geological Survey, Alaska Cooperative Fish and Wildlife Research Unit, University of Alaska, Fairbanks, AK, USA
J. A. O’Donnell, Arctic Network, National Park Service, Fairbanks, AK, USA
A. Rinke, Alfred Wegener Institute, Potsdam, Germany
K. Schaefer, National Snow and Ice Data Center, Cooperative Institute for Research in Environmental Sciences, University of Colorado, Boulder, CO, USA
J. Sky, University of Oxford, Oxford, UK
C. Tarnocai, AgriFoods, Ottawa, ON, Canada
M. R. Turetsky, University of Guelph, Guelph, ON, Canada
K. P. Wickland, U.S. Geological Survey, Boulder, CO, USA
C. J. Wilson, Los Alamos National Laboratory, Los Alamos, NM, USA
 S. A. Zimov, North-East Scientific Station, Cherskii, Siberia

WHAT: Interviewing and averaging the best estimates by world experts on how much permafrost in the Arctic is likely to melt and how much that will contribute to climate change.

WHEN: 26 March 2013

WHERE: Climactic Change, Vol. 117, Issue 1-2, March 2013

TITLE: Expert assessment of vulnerability of permafrost carbon to climate change (open access!)

We are all told that you should never judge a book by its cover, however I’ll freely admit that I chose to read this paper because the headline in Nature Climate Change was ‘Pandora’s Freezer’ and I just love a clever play on words.

So what’s the deal with permafrost and climate change? Permafrost is the solid, permanently frozen dirt/mud/sludge in the Arctic that often looks like cliffs of chocolate mousse when it’s melting. The fact that it’s melting is the problem, because when it melts, the carbon gets disturbed and moved around and released into the atmosphere.

Releasing ancient carbon into the atmosphere is what humans have been doing at an ever greater rate since we worked out that fossilised carbon makes a really efficient energy source, so when the Arctic starts doing that as well, it’s adding to the limited remaining carbon budget our atmosphere has left. Which means melting permafrost has consequences for how much time humanity has left to wean ourselves off our destructive fossil fuel addiction.

Cliffs of chocolate mousse (photo: Mike Beauregard, flickr)

Cliffs of chocolate mousse (photo: Mike Beauregard, flickr)

 How much time do we have? How much carbon is in those cliffs of chocolate mousse? We’re not sure. And that’s a big problem. Estimates in recent research think there could be as much as 1,700 billion tonnes of carbon stored in permafrost in the Arctic, which is much higher than earlier estimates from research in the 1990s.

To give that very large number some context, 1,700 billion tonnes can also be called 1,700 Gigatonnes, which should ring a bell for anyone who read Bill McKibben’s Rolling Stone global warming math article. The article stated that the best current estimate for humanity to have a shot at keeping global average temperatures below a 2oC increase is a carbon budget of 565Gt. So if all the permafrost melted, we’ve blown that budget twice.

What this paper did, was ask the above long list of experts on soil, carbon in soil, permafrost and Arctic research three questions over three different time scales.

  1. How much permafrost is likely to degrade (aka quantitative estimates of surface permafrost degradation)
  2. How much carbon it will likely release
  3. How much methane it will likely release

They included the methane question because methane has short term ramifications for the atmosphere. Methane ‘only’ stays in the atmosphere for around 100 years (compared to carbon dioxide’s 1000 plus years) and it has 33 times the global warming potential (GWP) of CO2 over a 100 year period. So for the first hundred years after you’ve released it, one tonne of methane is as bad as 33 tonnes of CO2. This could quickly blow our carbon budgets as we head merrily past 400 parts per million of CO2 in the atmosphere from human forcing.

The time periods for each question were; by 2040 with 1.5-2.5oC Arctic temperature rise (the Arctic warms faster than lower latitudes), by 2100 with between 2.0-7.5oC temperature rise (so from ‘we can possibly deal with this’ to ‘catastrophic climate change’), and by 2300 where temperatures are stable after 2100.

The estimates the experts gave were then screened for level of expertise (you don’t want to be asking an atmospheric specialist the soil questions!) and averaged to give an estimate range. For surface loss of permafrost under the highest warming scenario, the results were;

  1. 9-16% loss by 2040
  2. 48-63% loss by 2100
  3. 67-80% loss by 2300
Permafrost melting estimates for each time period over four different emissions scenarios (from paper)

Permafrost melting estimates for each time period over four different emissions scenarios (from paper)

Ouch. If we don’t start doing something serious about reducing our carbon emissions soon, we could be blowing that carbon budget really quickly.

For how much carbon the highest warming scenario may release, the results were;

  1. 19-45billion tonnes (Gt) CO2 by 2040
  2. 162-288Gt CO2 by 2100
  3. 381-616Gt CO2 by 2300

Hmm. So if we don’t stop burning carbon by 2040, melting permafrost will have taken 45Gt of CO2 out of our atmospheric carbon budget of 565Gt. Let’s hope we haven’t burned through the rest by then too.

However, if Arctic temperature rises were limited to 2oC by 2100, the CO2 emissions would ‘only’ be;

  1. 6-17Gt CO2 by 2040
  2. 41-80Gt CO2 by 2100
  3. 119-200Gt CO2 by 2300

That’s about a third of the highest warming estimates, but still nothing to breathe a sigh of relief at given that the 2000-2010 average annual rate of fossil fuel burning was 7.9Gt per year. So even the low estimate has permafrost releasing more than two years worth of global emissions, meaning we’d have to stop burning carbon two years earlier.

When the researchers calculated the expected methane emissions, the estimates were low. However, when they calculated the CO2 equivalent (CO2e) for the methane (methane being 33 times more potent than CO2 over 100 years), they got;

  1. 29-60Gt CO2e by 2040
  2. 250-463Gt CO2e by 2100
  3. 572-1004Gt CO2e by 2300

Thankfully, most of the carbon in the permafrost is expected to be released as the less potent carbon dioxide, but working out the balance between how much methane may be released into the atmosphere vs how much will be carbon dioxide is really crucial for working out global carbon budgets.

The other problem is that most climate models that look at permafrost contributions to climate change do it in a linear manner where increased temps lead directly to an increase in microbes and bacteria and the carbon is released. In reality, permafrost is much more dynamic and non-linear and therefore more unpredictable, which makes it a pain to put into models. It’s really difficult to predict abrupt thaw processes (as was seen over 98% of Greenland last summer) where ice wedges can melt and the ground could collapse irreversibly.

These kinds of non-linear processes (the really terrifying bit about climate change) made the news this week when it was reported that the Alaskan town of Newtok is likely to wash away by 2017, making the townspeople the first climate refugees from the USA.

The paper points out that one of the key limitations to knowing exactly what the permafrost is going to do is the lack of historical permafrost data. Permafrost is in really remote hard to get to places where people don’t live because the ground is permanently frozen. People haven’t been going to these places and taking samples unlike more populated areas that have lengthy and detailed climate records. But if you don’t know how much permafrost was historically there, you can’t tell how fast it’s melting.

The key point from this paper is that even though we’re not sure exactly how much permafrost will contribute to global carbon budgets and temperature rise, this uncertainty alone should not be enough to stall action on climate change.

Yes, there is uncertainty in exactly how badly climate change will affect the biosphere and everything that lives within it, but currently our options range from ‘uncomfortable and we may be able to adapt’ to ‘the next mass extinction’.

So while we’re working out exactly how far we’ve opened the Pandora’s Freezer of permafrost, let’s also stop burning carbon. 

Crash Diets and Carbon Detoxes: Irreversible Climate Change

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

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.

When the Party’s Over: Permian Mass Extinction

“The implication of our study is that elevated CO2 is sufficient to lead to inhospitable conditions for marine life and excessively high temperatures over land would contribute to the demise of terrestrial life.”

WHO: Jeffrey T. Kiehl, Christine A. Shields, Climate Change Research Section, National Center for Atmospheric Research, Boulder, Colorado, USA

WHAT: A complex climate model of atmospheric, ocean and land conditions at the Permian mass extinction 251 million years ago to look at CO2 concentrations and their effect.

WHEN: September 2005

WHERE: Geological Society of America, Geology vol. 33 no. 9, September 2005

TITLE: Climate simulation of the latest Permian: Implications for mass extinction

The largest mass extinction on earth occurred approximately 251million years ago at the end of the Permian geologic era. Almost 95% of all ocean species and 70% of land species died, and research has shown that what probably happened to cause this extinction was carbon dioxide levels.

As the saying goes; those who do not learn from history are doomed to repeat it, so let’s see what happened to the planet 251 million years ago and work out how we humans can avoid doing it to ourselves at high speed.

This research paper from 2005 did the first comprehensive climate model of the Permian extinction, which means their model was complicated enough to include the interaction between the land and the oceans (as different to ‘uncoupled’ models that just looked at one or the other and not how they affected each other).

The researchers used the CCSM3 climate model that is currently housed at the National Centre for Atmospheric Research (NCAR) and is one of the major climate models currently being used by the IPCC to look forward and model how our climate may change with increasing atmospheric carbon pollution (or emission reduction). They organised their model to have ‘realistic boundary conditions’ for things like ocean layers (25 ocean layers for those playing at home), atmospheric resolution and energy system balance. They then ran the simulation for 900 years with current conditions and matched it with observed atmospheric conditions and got all of their data points correct with observed data.

Then, they made their model Permian, which meant taking CO2 concentrations and increasing them from our current 397ppm to 3,550ppm which is the estimated CO2 concentrations from the end of the Permian era.

What did ramping up the CO2 in this manner do for the planet’s living conditions in the model? It increased the global average temperature to a very high 23.5oC (the historic global average temperature for the Holocene (current era) is 14oC).

Oceans
Changing the CO2 concentrations so dramatically in the model changed the global average ocean surface temperature 4oC warmer than current conditions. Looking at all the ocean layers in their model, the water was warmer in deeper areas as well, with some areas at depths of 3000m below sea level measuring 4.5-5oC where they are currently near freezing.

The greatest warming in the oceans occurred at higher latitudes, where ocean temps were modelled at 8oC warmer than present, while equatorial tropical oceans were not substantially warmer. The oceans were also much saltier than they currently are.

The big problem for all of the things that called the ocean home at the end of the Permian era is the slowing of ocean circulation and mixing. Currently, dense salty water cools at the poles and sinks, oxygenating and mixing with deeper water allowing complex organisms to grow and live. If this slows down, which it did in this model, it has serious consequences for all ocean residents.

Current ocean circulation patterns (NOAA, Wikimedia commons)

Current ocean circulation patterns (NOAA, Wikimedia commons)

Their Permian model measured ocean overturning circulation around 10 Sv (million cubic metres per second), whereas current ocean overturning circulation is around 15-23 Sv. The researchers think the ocean currents could have slowed down enough to create anoxic oceans, which are also known as ‘ocean dead zones’ or ‘Canfield Oceans’, and stated that it set the stage for a large-scale marine die off.

Land
If the end of the Permian was pretty nasty for ocean residents, how did it fare for land-dwellers? What happened to the tetrapods of Gondwanaland? Well it looked really different to how earth looks today.

Permian land mass (Wikimedia commons)

Permian land mass (Wikimedia commons)

There were deciduous forests at high latitudes, and the elevated CO2 in the model was the dominant reason for warm, ice free Polar Regions (which also hindered ocean circulation). Land surface temperatures were between 10 – 40oC warmer than they are today. In their model, dry sub-tropical climates like the Mediterranean or Los Angeles and Southern California were much hotter, with the average daily minimum temperatures around 51oC. Yes, Los Angeles, your overnight low could be 51oC.

Understandably, the authors state that ‘these extreme daily temperature maxima in these regions could contribute to a decrease in terrestrial flora and fauna’, which is scientist for ‘it’s so damn hot outside nothing except cacti can grow’.

All of these changes were run over a 2,700 year period in the model, which if you take the 2005 CO2 concentration of 379ppm as your base is an increase of 1.17ppm per year.

This is the important bit to remember if we’re going to learn from history and not go the way of the Permian residents. Our current rate of increase in CO2 concentrations is 2ppm per year, which means we are on a super speed path to mass extinction. If we continue with business as usual, which has been aptly renamed ‘business as suicide’ by climate blogger Joe Romm, we will be at the end of the next mass extinction in around 1,500 years.

Where humanity is headed (from Royal Society Publishing)

Where humanity is headed (from Royal Society Publishing)

All we need to do to guarantee this being the outcome of all of humanity is keep the status quo and keep burning fossil fuels and the entire sum of humans as a species on this planet will be a tiny geological blip where we turned up, became the most successful invasive species on the globe, burned everything in sight and kept burning it even when we knew it was killing us.

However, I think this part from the paper’s conclusion should give most of us a pause for thought;

 ‘Given the sensitivity of ocean circulation to high-latitude warming, it is hypothesized that some critical level of high-latitude warming was reached where connection of surface waters to the deep ocean was dramatically reduced, thus leading to a shutdown of marine biologic activity, which in turn would have led to increased atmospheric CO2 and accelerated warming.’

As a species, if we are going to survive we need to make sure we do not go past any of those critical levels of warming or tipping points. Which means we need to make sure we stop burning carbon as fast as possible. Otherwise, T-Rex outlasted us as a species by about two million years which would be kinda embarrassing.

Sleepwalking off a Cliff: Can we Avoid Global Collapse?

‘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?