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?

World Bank Wants off the Highway to Hell

“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. 

Getting off the Highway to Hell

Climate change is kicking in faster that expected, and the global threshold of 2oC is now considered the line between dangerous and extremely dangerous climate change. What will it take to avoid this highway to hell?

WHO: Kevin Anderson, Tyndall Centre for Climate Change Research, School of Mechanical, Aerospace and Civil Engineering, University of Manchester, UK  and School of Environmental Sciences and School of Development, University of East Anglia, Norwich, UK
Alice Bows, Sustainable Consumption Institute, School of Earth, Atmospheric and Environmental Sciences, University of Manchester, UK

WHAT: Some carbon budgetary truths for the world – how much do we have left to burn and when do we have to stop it by?

WHEN: 13 January 2011

WHERE: Philosophical Transactions of the Royal Society of London A: Mathematical, Physical and Engineering Sciences. Phil. Trans. R. Soc. A vol. 369, no. 1934

TITLE: Beyond ‘dangerous’ climate change: emission scenarios for a new world

Have you ever seen one of those reality TV shows where a person who is hopeless with money is given some budgeting ‘real talk’ and taught to live within their means? This paper is going to do that for your carbon budgets.

Humans love to procrastinate – we’re great at it. And despite all the new semester resolutions of keeping on top of the work this time, it inevitably leads to last minute late night exam cramming. However, it looks like climate change doesn’t have this problem. Currently, the arctic ‘death spiral’ is decades ahead of melting from climate change schedule, the Great Barrier Reef in Australia is already 50% bleached and dead and the drought predictions for the south west of the USA are also ahead of schedule.

This means that the globally declared point that we shall not pass for global warming of 2oC has now been upgraded from the line between acceptable and dangerous climate change to the border between dangerous and extremely dangerous climate change. Congratulations on the promotion 2oC?

So now that procrastinating past 2oC is looking like a dangerous decision, what do we need to do about it?

These researchers looked at the Copenhagen Accord from the 2009 UNFCCC negotiations (remember the non-binding one?) and it states that we must act to prevent going above 2oC of global warming on the basis of science and equity. Since it’s the cumulative emissions that are really going to bite us, the researchers decided to work from the end point of preventing 2oC in different scenarios and then worked the carbon budgets backwards to see if we have a chance of meeting the 2oC goal and how we could do it.

The UN separates the UNFCCC agreement into two groups: Annex 1 countries (which is the developed world) and non-Annex 1 countries (the developing world). Keeping with the ideal of equity, the scenarios in this paper allow for emissions to grow in the developing world longer than they can grow in the first world. However, the paper did point out that if developing nations grow into developed fossil fuel economies, their emissions will outstrip world emissions from the industrial revolution to the 1950s, so mitigation in the developing world is going to be increasingly important really fast.

The paper does three scenarios and then tweaks each one. The first scenario only counts CO2 emissions which allows it to be more accurate, but doesn’t include other greenhouse gases. The second scenario includes all six main greenhouse gases which makes it less accurate (more variables) but also more realistic. The third scenario looks at what is currently considered ‘politically possible’ in terms of emissions reductions. It gets long, so I’ll provide a handy summary table too!

Interestingly, the Bill McKibben budget of 565 Gigatonnes (Gt) of carbon (2055 Gt of CO2) from his Rolling Stone article is not considered here, because the chance of blowing past the 2oC limit is too high.

Here’s how they worked out:

CO2 only with a small budget
If we have a carbon budget of 1321 Gt CO2 and emissions from the developing world grow at less than 3% per year until 2015, and reduces by 6% per year after 2020, and the first world reduces their emissions from now by 11% per year, we have a 36% of still causing extremely dangerous climate change.

If we do the above but the developing world’s emissions grow until 2025, they’ve spent the whole carbon budget at once and we blow past 2oC. But if the developing world’s emissions grow at less than 1% until 2025 and they reduce their emissions by 7-8% per year while the first world reduces by 11% per year from now, then there’s a 37% chance of causing extremely dangerous climate change. The researchers described this one as ‘plausible but highly unlikely’.

CO2 with a small budget scenarios with a 36% chance (a), blowing the budget (b) and a 37% chance (c). Blue line is first world emissions, red line is developing world emissions, dotted line is global emissions including deforestation (from paper)

CO2 only with a bigger budget
So what happens if we’re a bit more realistic and increase the burnable budget a bit? If we have a carbon budget of 1578 Gt CO2 and emissions from the developing world grow by 4% per year until 2015, first world emissions don’t grow and global emissions reduce by 5-6% per year from 2015, we have a 50% chance of causing extremely dangerous climate change.

If there is a 5 year delay and emissions in the developing world grow by 4% per year until 2020, and then reduce by 7-8% per year after that while the first world reduces by 7-8% per year from 2010 (yes, from two years ago), then the 5 year delay bumps us up to a 52% chance of causing extremely dangerous climate change, even with the faster reductions. Given we needed to start two years ago, that one’s out too.

If the developing world misses the 7-8% per year reduction targets above and only reduce emissions by 4-5% per year, they spend all the carbon budget and we either blow past 2oC or first world emissions fall immediately to zero in 2015. Also not workable then.

CO2 with a bigger budget with a 50% chance (a), with a 52% chance (b) and blowing the budget (c) (from paper)

Counting all the gases with a small budget
If we include all the other greenhouse gases like methane and nitrous oxide (which means we start talking CO2 equivalent because otherwise it’s really unwieldy to count), we can also count emissions for food production for the 9 billion people we’re going to have on the planet by 2050, which will be around 6 Gt Co2e per year (animals fart methane and crops need nitrogen among other things) and further reduces the carbon budget.

If the budget is 1376 Gt CO2e and the developing world’s emissions grow at less than 3% per year until 2015, emissions in the first world need to drop to zero in 2015. So that budget is bust too.

All GHGs with a small budget which goes bust

Counting all the gases with a bigger budget
If the budget is 2202 Gt CO2e and the developing world increases emissions by less than 3% per year until 2015 and then decreases by 6% per year and the first world reduces emissions by 3% per year until 2020 and then 6% per year after that, we have a 39% chance of causing extremely dangerous climate change.

If the developing world grows at 3% per year until 2020 and then reduces emissions by 6% per year, the first world needs to reduce emissions by 10% per year from 2010. So that budget is also bust.

If the developing world only grows at 1% per year until 2025 and reduces by 4-5% per year, the first world’s emissions need to be flat to 2014 and reduce by 6% per year after that. If we could do that we would have a 38% chance of causing extremely dangerous climate change.

All GHGs with a bigger budget 39% chance left, busting budget middle, 38% chance right (from paper)

But here’s the problem; currently what is considered politically and economically possible for reducing carbon emissions is reductions of 3% per year. Which blows all of these budgets.

If we only counted the CO2,had a budget of 2741 GtCO2 (which is higher than any of the budgets above) and reduced our emissions by 3% per year from 2015 in the first world and 2030 in the developing world, we have an 88% chance of causing extremely dangerous climate change.

The politically feasible options counting CO2 left and all GHGs right, both with 88% chances of blowing 2oC (from paper)

If we counted all the gases and had a larger budget of 3662 Gt CO2e with reductions of 3% per year as above, we get the same result. This means that business as usual is actually business on the way to 4oC of global warming, which has been described by the one of the authors of this paper Kevin Anderson as

incompatible with organized global community, is likely to be beyond ‘adaptation’, is devastating to the majority of ecosystems & has a high probability of not being stable i.e.  4°C would be an interim temperature on the way to a much higher equilibrium level’

Scenarios in table form for quick reference (click for bigger version)

Basically, what we’re currently doing is going to fail spectacularly in the near future. And since physics doesn’t negotiate we can’t get an extension on this one. If we are to make any of the carbon budgets above, society needs to be reducing carbon emissions at a much higher rate than we currently are.

I’d like to finish with the conclusion from the paper, because I think their version of climate tough love is excellent:

This paper is not intended as a message of futility, but rather a bare and perhaps brutal assessment of where our ‘rose-tinted’ and well intentioned (though ultimately ineffective) approach to climate change has brought us. Real hope and opportunity, if it is to arise at all, will do so from a raw and dispassionate assessment of the scale of the challenge faced by the global community. This paper is intended as a small contribution to such a vision and future of hope.

Too Hot in Texas

New modelling of climate change effects on mosquito populations in the United States has surprising results – it might get too hot in summer even for the mosquitoes

WHO: R A Erickson, S M Presley, Department of Environmental Toxicology, and Institute of Environmental and Human Health, Texas Tech University, Lubbock, Texas
K Hayhoe, Department of Political Science, Texas Tech University, Lubbock, Texas
L J S Allen, Institute of Environmental and Human Health, and Department of Mathematics and Statistics, Texas Tech University, Lubbock, Texas
K R Long, Department of Mathematics and Statistics, Texas Tech University, Lubbock, Texas
S B Cox, Department of Environmental Toxicology, and Institute of Environmental and Human Health, Texas Tech University, Lubbock, Texas and Research and Testing Laboratory, LLC, Lubbock, Texas

WHAT: Population modelling for the Asian Tiger mosquito which carries dengue fever under two climate change scenarios

WHEN: 5 July 2012

WHERE: Environmental Research Letters, Vol. 7, No. 3 (July-Sept 2012)

TITLE: Potential impacts of climate change on the ecology of dengue and its mosquito vector the Asian tiger mosquito (Aedes albopictus)

This group of researchers in Texas decided it would be interesting to look at different climate change emissions scenarios from the IPCC and see what the effect of climate change might be on everybody’s ‘friend’ the Asian Tiger mosquito. For those of you who haven’t met the Asian Tiger mosquito, it is the type that carries dengue fever, which makes you very sick. So understandably, how climate change affects the population spread of this mosquito is pretty important.

The Asian Tiger mosquito is not your friend (Wikipedia)

The researchers looked at three localised areas in the US to run their model – Lubbock TX (where their University is), Atlanta GA, and to look at the potential geographical spread of the mosquito; Chicago IL.

Many of the predicted consequences of climate change are currently happening decades ahead of schedule, and one of the consequences is the expansion of the tropical belt by around 2- 4.8o latitude since 1979. This wasn’t expected to occur until 2100, so it means mosquitoes could be moving north faster than previously predicted.

The climate scenarios used were the A1FI (high emissions) and B1 (medium emissions) from the IPCC Special Report on Emissions Scenarios, which relate to approximately 970ppm (A1FI) and 550ppm (B1) of CO2 in the atmosphere. To give some context for those numbers, we’re currently sitting at 391ppm. 550ppm is where feedback loops have already kicked in and there are large ocean ‘dead zones’ where there’s not enough oxygen for plant and animal life. 970ppm is the IPCC’s ‘worst case scenario’ where there is mass biodiversity loss and a high likelihood of mass extinction events.

IPCC Emissions Scenarios A1FI (above) and B1 (below)

Anyway, back to mosquitoes. The researchers used three of the world’s best and most detailed climate models; the CM3 model from the UK’s Hadley Centre, the National Centre for Atmospheric Research model in Colorado, and the National Oceanic and Atmospheric Administration’s CM2.1 model. They used the mean temperature data from their three locations and combined it with the climate model to work out what the average temperatures might look like under the scenarios. Then they applied those conditions to mosquito populations to see what might change.

What they found was very interesting, and not what the researchers had originally expected. While the population size and duration of the mosquito season in Chicago increased across the board along with the potential dengue fever outbreak size, in Lubbock and Atlanta the mid-summer temperatures got too hot even for the mosquitoes.

Chicago (left) and Lubbock (right) with mid and end of century predictions. Chicago has an increase in mosquito population while Lubbock has a noticeable mid-summer die-off of mosquitoes (from paper)

While the mosquito season in Lubbock started earlier and had a potential for greater dengue fever outbreaks, the super-hot summer temperatures under both of the climate change scenarios modelled led to mosquitoes dying and a reduction in potential dengue fever outbreaks. This could have many social and health policy ramifications in the areas studied and also shows that the local level effects of climate change may manifest in ways we haven’t previously thought of.

Humans are notoriously difficult to predict and we don’t know yet what humanity will do about climate change in the near future. This gets combined with natural systems and feedbacks that are highly integrated and complex which means one seemingly unrelated process may be triggered in another previously unrelated process.

However, complexity doesn’t mean that models aren’t relevant or useful and the proverbial baby should be thrown out with the bathwater. Models give us a range of possibilities to plan for and allow humans the opportunity to act in our own long term best interests.

Currently, we’re not acting for our long term well being, and humanity is currently burning carbon at a rate that matches or beats the A1FI high emissions scenario that very probably leads to mass extinction, including humans. Which means that now would be the time to stop burning fossil fuels. Before Texas becomes so scorching hot that even the mosquitoes die from the mid-summer heat.