Tag Archives: mass extinction

When the Party’s Over: Permian Mass Extinction

Posted on by
1

“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?

Posted on by
2

‘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?

Too Hot in Texas

Posted on by
2

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.