Category Archives: diseases

Much ado about phosphorus

Posted on by
3

‘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.

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?

Don’t go in the Water

Posted on by
2

Warming sea surface temperatures in low-salinity oceans like the Baltic Sea is increasing cases of Vibrio bacteria infections

WHO: Craig Baker-Austin, Nick G. H. Taylor, Rachel Hartnell, Centre for Environment Fisheries and Aquaculture Science, Weymouth, Dorset, UK,
Joaquin A. Trinanes, Laboratory of Systems, Technological Research Institute, Universidad de Santiago de Compostela, Spain, National Oceanic and Atmospheric Administration, National Environmental Satellite Data and Information Service, CoastWatch, Maryland, USA
Anja Siitonen, Bacteriology Unit, National Institute for Health and Welfare (THL), Helsinki, Finland
Jaime Martinez-Urtaza  Instituto de Acuicultura, Universidad de Santiago de Compostela, Spain

WHAT: Establishing patterns between Vibrio bacteria infection outbreaks and climate change in the Baltic Sea to be able to predict future outbreaks.

WHEN: January 2013

WHERE: Nature Climate Change, Vol 3, January 2013

TITLE: Emerging Vibrio risk at high latitudes in response to ocean warming (subs. req)

Imagine that it’s a hot summer’s day in Northern Europe. The heat wave has lasted for more than three weeks now and you’re just dying to get into the ocean for a swim to cool off, except that you can’t, because there’s been a bacteria outbreak in the water and going swimming will make you sick.

Looks great! Can’t swim. (photo: flickr)

Looks great! Can’t swim. (photo: flickr)

It doesn’t sound like fun does it? But it’s happening increasingly in the Baltic Sea, and it looks like climate change is providing the exact conditions these bacteria love.

Vibrio is a type of bacteria that grows really well in warm (>15oC) low-salinity (<25 parts per trillion salt) water. The most common type in estuaries and other shallow water is Vibrio vulnificus, which is related to the same bacteria that causes cholera (Vibrio cholerae). Not a nice family, really.

When you swim in water that has Vibrio bacteria, it immediately gets excited (yes, I’m aware that bacteria don’t have feelings) about any cuts or wounds you have and infects them giving you symptoms like vomiting, diarrhea, abdominal pains and blistering dermatitis. Well, that’s a way to really ruin your summer.

If you’re really unlucky or immuno-compromised, Vibrio will give you blistering skin lesions, septic shock (life threatening low blood pressure) and possibly kill you 25% of the time. It’s an efficient bacterium though, and will kill you in only 48hrs.

Vibrio vulnificus (Wikimedia commons)

Vibrio vulnificus (Wikimedia commons)

So why is Vibrio moving into the Baltic Sea more often? Climate change, combined with location.

The Baltic Sea is the largest low-salinity marine ecosystem on Earth, and is surrounded by highly populated countries, meaning there are 30million people living within 50km of the shores of the sea. The Baltic Sea is also warming rapidly.

The Baltic Sea (Google maps)

The Baltic Sea (Google maps)

The researchers found that the sea surface temperature has been warming in excess of 1oC per decade, which is seven times the global average rate of warming. The rate is also increasing. From 1850 to 2010, the rate of warming was .51oC per century. The warming between 1900 to 2010 was at a rate of .77oC per century, and more recently the warming from 1980-2010 has been at a pace of 5oC per century, which is scarily fast for planetary systems.

Their data shows that for every 1oC increase in the summer maximum sea surface temperature, the rate of observed Vibrio infections increased by almost 2 times. This of course, gets compounded with the fact that increased summer maximum sea surface temperatures mean the air temperature is also hotter, and a hotter summer means more people head to the beach and get infected.

Even worse, recent research shows that some Vibrio bacteria’s ‘pathogenic competence’ (which is scientist for how good it is at infecting you) could be improved by increased temperatures.

Which all adds up to a nasty sequence of events where many more people than usual get nasty skin lesions. So what should we do about it? The researchers suggest monitoring conditions and sending out health advisories for when the sea surface temperatures are >19oC for three weeks or more as well as using predictive models to try and work out where/when the worst outbreaks might occur.

I don’t know about you, but nasty bacterial infections from a warmer ocean on a slowly cooking planet doesn’t sound like a good idea to me. So I’d also like to suggest we stop burning carbon so I and the people of Northern Europe can continue to swim in the summer.

World Bank Wants off the Highway to Hell

Posted on by
1

“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. 

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.