Why Monster Hurricanes Like Patricia Are Expected On A Warmer Planet

Fairfax - Chris Mooney


Hurricane Patricia makes landfall as a category 5 storm near the port of Manzanillo on Mexico's Pacific coast.
First there was Supertyphoon Haiyan - which peaked out at 170-knot or 315 km/h mile-per-hour winds in 2013 as it slammed the Philippines. And now there is Patricia, forecast to soon hit Mexico, with currently estimated maximum sustained wind speeds of 175 knots or more than 324 km/h.
It is officially the strongest hurricane ever measured by the U.S. National Hurricane Center, based on both its wind speed (175 knots) and its minimum central pressure (880 millibars). The wind measurement "makes Patricia the strongest hurricane on record in the National Hurricane Center's area of responsibility (AOR) which includes the Atlantic and the eastern North Pacific basins," the center said this morning.
And in this case the measurement has added weight because it is based on data collected from an aircraft, rather than mere satellite imagery. "We would like to acknowledge deeply the Air Force Hurricane Hunters for their observations establishing Patricia as a record-breaking hurricane. Clearly, without their data, we would never have known just how strong a tropical cyclone it was," wrote National Hurricane Center forecaster Richard Pasch this morning.

NASA satellite imagery show super Hurricane Patricia as it neared the Mexican coast. Photo: NASA

So how could this happen? The first reason is the presence of an El Nino year which generally leads to hyperactive hurricane activity in the Eastern Pacific basin, says Kerry Emanuel, an MIT hurricane expert, by email. Emanuel has derived a way of measuring the maximum potential intensity that a hurricane can achieve, in light of the climatic conditions in which it forms, which include the sea temperature and also the temperature high in the atmosphere above the storm.
"Potential intensity was particularly high in the region where Patricia developed," Emanuel says. He provided this figure to underscore the point:
So what does this say about climate change?
Certainly, record-breaking hurricanes raise questions about longstanding predictions that global warming, by raising ocean temperatures, should also strengthen these storms. The issue, however, is beset by data-related difficulties, since storm measurement techniques are continually improving and are also highly variable around the world - thus, hurricane hunter flights are far more common in the Atlantic than in the Northeast Pacific, where Patricia formed.
Still, there are widespread predictions that hurricanes should become stronger, on average, in a warmer world. Summarizing the current research, the Geophysical Fluid Dynamics Laboratory of the National Oceanic and Atmospheric Administration puts it this way: "Anthropogenic warming by the end of the 21st century will likely cause tropical cyclones globally to be more intense on average. . ..This change would imply an even larger percentage increase in the destructive potential per storm, assuming no reduction in storm size."
But of course, it's not the end of the 21st century - it's 2015. So are we seeing the change already, with Haiyan and now Patricia?
"The fact that we have broken records now in the eastern and western Pacific is curious, but we are still dealing with the statistics of small numbers so inferences are dangerous," Emanuel says by email. Emanuel also cautions that because most Eastern Pacific storms are not measured by aircraft, there could have been a stronger one in the past that was not detected. Nonetheless, he recently published research suggesting the possibility of hyper-strong hurricanes in certain regions as global warming continues.
While one storm is only one storm and can never substitute for a comprehensive statistical analysis, the fact remains that the link between warm seas and strong storms - the theoretical reason for believing hurricanes will worsen due to climate change - is starkly apparent in this case.
"The [sea surface temperatures] are so high over such huge areas, that the moisture flowing into the storm, that provides it primary fuel, must be higher than it has ever been before," says Kevin Trenberth, a climate researcher at the National Center for Atmospheric Research, by email. "It still requires the right set up to convert that into an intense storm but the environment is surely ripe. That consists, of course, of a substantial El Nino-related component but also the background global warming that has a memory through the ocean heat content."
Trenberth points out that ocean surface temperatures in the region are warmer than 30 degrees Celsius, or 86 degrees Fahrenheit, "the warmest anywhere around." "The subsurface ocean is exceptionally warm as well," he adds.
"As ocean temperatures continue to warm as a result of human-caused climate change, we expect hurricanes to intensify, and we expect to cross new thresholds. Hurricane Patricia and her unprecedented 200 mile-per-hour sustained winds, appears to be one of them now, unfortunately," adds Michael Mann, a climate researcher at Penn State University.
Scientists will never attribute one single event to climate change or say that it was caused by a warming planet; and with this event as with all weather events there are multiple causes, most prominently El Nino.
Nonetheless, we can say this: Record-setting hurricanes like Patricia are consistent with one major prediction that climate researchers have made for some time about the consequences of a warming world.

Climate Change Is A Reverse Robin Hood For Poor Countries

SBS - Aamna Mohdin

The future doesn't look good for certain countries.Climate change is a reverse Robin Hood: stealing from the poor countries and giving to the rich ones.  

File photo of a failed grain crop in central New South Wales. (AAP)

Just when you thought the news about climate change couldn’t get any worse, consider this.
Not only will global warming put a massive dent in the world’s GDP over the coming decades, but it “is essentially a massive transfer of value from the hot parts of the world to the cooler parts of the world,”according to a new study in Nature. “This is like taking from the poor and giving to the rich.”
Researchers Stanford University analyzed 166 countries over a 50-year period (from 1960 to 2010) and compared economic output when country’s experienced normal temperature to abnormally cold or warm temperatures. Controlling for factors such as geography, economic changes, and global trade shifts, they found the optimum temperature where humans are good at producing stuff: 55ºF (13ºC). Applying this finding to climate change forecasts, they found that 77% of countries will experience a decline in per capita incomes by 2099, with the average person’s income shrinking by 23%. Unusually high temperatures will hurt agriculture, economic production, and overall health, researchers say.

Stanford

However, some cold countries will benefit hugely, including Mongolia, Finland, Iceland, and Canada. Most European countries will see slight economic gains.
The Middle East, Africa, Asia and South America, where the world’s poorest are concentrated, are expected to be hit hardest by climate change. These countries are either already at or passed the economic Goldilocks temperature, so productivity will only fall as temperatures increase.

By showing how future climate change will cost the global economy, researchers hope policymakers will significantly invest in reducing emissions. World leaders are set to convene in Paris to negotiate aninternational climate treaty next month. Many have promised to cut emissions, but environmentalists have warned that current pledges aren’t enough to mitigate the worst-case scenario.

Australia's Military Stuck In The 'Wilderness' Over Climate Change, Former ADF Chief Says

Fairfax - Peter Hannam

Military leaders are concerned that planning for the effects of global warming has been stymied by politics.
Photo: Ian Hitchcock

• Diggers face their next battle: extreme weather

Australia's military planners have neglected climate change threats to the country and neighbours, leaving forces under-prepared for imminent and far-ranging challenges, say two retired senior officers – including a former Australian Defence Force chief.
"I don't think it's any secret that we've spent three years in the wilderness" on these issues, Chris Barrie, a former admiral who served as ADF chief from 1998 to 2002, told Fairfax Media.

Retired admiral Chris Barrie says climate change has not got the attention it deserves in the ADF.
Photo: Andrew Taylor

Admiral Barrie said a changing climate would place limits on the ADF's capabilities just as demands for involvement on humanitarian and security grounds increased. The risks range from rising sea-levels inundating low-lying military bases to extreme heat affecting troops' health.
Former prime minister Tony Abbott's aversion to making global warming a priority meant the issue was downplayed. "When the Abbott government said you will not use the words 'climate change', the senior leadership had to do as it was directed, but at the same time they know this is important work," Admiral Barrie said.
The challenges may be illustrated within weeks if - as expected by aid groups and others - Papua New Guinea seeks help from Australia to deliver urgently needed food to remote highland villages hard-hit by the unfolding El Nino-linked drought.
"If the situation gets out of hand, and by that I mean people are starving, they will act unlawfully and then it turns out in a monster security situation," he said.
Michael Thomas, an army major who retired in June after 22 years of service, said the politicisation of climate change had been "a huge distraction to defence".
"There are pockets of interest within the military on the subject but it's not something that has captured the attention of our senior leadership," Major Thomas said.
Both former military leaders outlined concerns in a recent report they wrote for the Climate Council and will lead a two-day panel at the Australian Defence Force Academy next week. They also detect a change of policy under new Prime Minister Malcolm Turnbull.
A Defence spokesperson said the department "has been actively monitoring and addressing the impacts of climate change for a number of years".
The upcoming Defence White Paper - originally due for completion last September - will address the full ranges of challenges facing the ADF out to 2035 "including the security implications of climate variability and extreme weather events in our region and beyond", the spokesperson said.

The Graphic That Shows Why 2015 Global Temperatures Are Off The Charts

Fairfax - Peter Hannam

El Nino effects shown in satellite data
NASA has released animation based on satellite data showing this year's El Nino is likely to be just as devastating as the strongest on record.

If there is one chart that might finally put to rest debate of a pause or "hiatus" in global warming, this chart created by the US National Oceanic and Atmospheric Administration has just supplied it.
For years, climate change sceptics relied on a spike in global temperatures that occurred during the monster 1997-98 El Nino to say the world had stopped warming because later years struggled to set a higher mark even as greenhouse gas emissions continued to rise.

The intensifying El Nino has helped drive global temperatures to yet another record monthly high. Photo: Leigh Henningham

Never mind that US government scientists found the hiatus was an illusion because the oceans had absorbed most of the extra heat that satellites could tell the Earth was trapping.
Nor that 2005, 2010 and 2014 all set subsequent records for annual heat.Those record years were too incrementally warmer compared with the 1997 mark to satisfy those who wanted to believe climate change was a hoax.
But it is 2015, which is packing an El Nino that is on track to match the record 1997-98, that looks set to blow away previous years of abnormal warmth.
"This one could end the hiatus," said Wenju Cai, a principal research scientist specialising in El Nino modelling at the CSIRO.
"Whether it beats [the 1997-98 El Nino] will be academic - it's already very big."
NOAA data released overnight backs up how exceptional this year is in terms of warming, with September alone a full quarter of a degree above the corresponding month in 1997.
As the chart above shows, for the first nine months, 2015 has easily been the hottest year on record, with sunlight second.

Monster El Nino
Australia's Bureau of Meteorology said this month that the El Nino was now on course to challenge the 1997-98 event as the strongest on record, and was not expected to peak until late this year.
This would suggest that, short of a major disruptive event such as a huge volcanic eruption, 2015 will easily eclipse heat records in previous years.
The projection looks likely to be affirmed further before the global climate talks in Paris, which are scheduled to begin on November 30.
Almost 200 nations will be negotiating on a new treaty to stem the emissions of greenhouse gases that are driving temperatures higher and disrupting climate patterns around which humans have built their civilisation.

Mostly anomalous in past 1629 months
September was not only the seventh month so far this year to set a new record for heat, it was also the most anomalously hot month in 135 years of data, NOAA said.
"This marks the fifth consecutive month a monthly high temperature record has been set and is the highest departure from average for any month among all 1629 months in the record that began in January 1880," NOAA said in a statement.
Average sea- and land-surface temperatures last month were 0.9 degrees above the 20th-century average, pipping the previous hottest September - set only a year ago - by 0.12 degrees.
The abnormal warmth was particularly notable in the central and eastern equatorial Pacific, where the El Nino weather event continues to intensify.

For the first nine months of 2015, average surface temperatures are running at 0.85 degrees above the 20th-century average, exceeding the previous equal warm stints in 2010 and 2014 by 0.12 degrees, NOAA said.
During El Nino years, the Pacific Ocean tends to absorb less heat or release some back to the atmosphere as a result of changing easterly wind patterns. One consequence of those reversed or stalled winds is that the western Pacific tends to be drier and hotter, while nations on the eastern Pacific fringe usually receive above-average rain.
Australia was not exceptionally warm last month, with mean temperatures 0.2 degrees above the 1961-90 average. However, it was the third driest September in records going back to 1910 with little more than one-third of the average rainfall nationwide, the bureau said in its monthly report.
October got off to a record hot start for southern Australia, with many records falling for early-season heat, lifting concerns about an active fire season ahead.

Temperatures topped up
El Ninos typically add 0.1-0.2 degrees to the background global warming. US climate expert John Abraham has estimated how year-to-date temperatures are adding another step-up to temperatures, as seen in this chart published by Think Progress.

Climate change sceptics will probably not concede in their battle to avoid action to curb emissions.
Satellite or meteorological data must have been manipulated, the oceans might be producing chemical compounds never detected before that counter carbon dioxide, or perhaps the sun is about to burn a lot less brightly.
Still, they now have one more inconvenient chart they have to find a reason to ignore.

Climate Change Is Going to Be Expensive—For Everybody

Wired - Nick Stockton

A farmer examines his wheat field which failed due to drought in Rochester, Australia. Jason South/Getty Images

Hot weather sucks. Crops droop. Work slows down. People get testy. And it’s bad for business.
So bad, in fact, that higher temperatures from climate change are going to be an economic gut punch for many countries, according to a paper published today in Nature. The poorest countries—most of which are also already pretty warm—will suffer the most. But even rich countries with their cubicles and air conditioning are going to feel the burn.
Climate change will hit every level of an economy. Mentally and physically people work worse when they are hot. Rising seas and fiercer storms chew up infrastructure. And agricultural effects like crop failures reach far beyond borders. But all that stuff is years away, right?
Wrong. As deniers like to say (maybe even in the comments!), climate is always changing. And it turns out that these changes show up in the economic record. The new study compared annual temperature to annual GDP for every country. “What we found is that temperature has played an important role in shaping GDP output in the last 50 years,” says Marshall Burke, economist at Stanford University and co-author of the study.
Of course, the relationship between temperature and GDP isn’t linear. The study found that economic growth has a sweet spot: Around 55˚F. If the average annual temperature falls above or below that, GDP starts to taper off—slow at first, then very fast. “The graph looks like a strong inverted U,” says Edward Miguel, economist at UC Berkeley and another co-author of the study. At either end, the GDP remains fairly stable between 32 and 77 degrees F, but drops rapidly beyond those boundaries.
This means that how poorly your country fares under climate change depends on its starting average temperature. “At colder temperatures, say Northern Europe, these countries grew a little bit faster when temperatures were warmer,” says Burke. By comparison, much of the developing world is already pretty warm, so its prospects are pretty grim.
But wait, is Northern Europe going to get richer because it gets warmer, or because it’s already rich? “This is one thing we tried to be really careful with,” says Burke. In their statistical analyses, he and his co-authors controlled for things like preexisting wealth. Temperature is only one variable affecting GDP. “Culture matters, institutions matter, policy choices matter,” says Burke. “What we do find is looking historically, temperature matters a lot.” Which is important if the future world responds to temperature changes like the past world has.
And not all rich countries are going to get richer. Part two of the study takes historical correlations between temperature and GDP and projects them forward under different climate models. In them, the economic wealth of countries like the US or China can’t compensate for their latitudinal girth. Both fare poorly in the “business as usual” emissions scenario explored in the study. “There will still be a number of days where Alabama or Texas are really hot, even if all of the US is still kind of cold,” says Miguel. And over the course of the year, as the years go on, the overall area of the US experiencing extremely hot days will increase. GDP suffers accordingly.
Previous attempts to put climate change in terms of GDP have tripped over the jump from micro to macro. For example, how do a heat-struck worker in Arizona and a failed soy crop in Kansas and a stronger-than-average hurricane in Louisiana influence economic performance at a national level? In trying to add up all those microeconomic effects, studies can under- or overstate an inputs importance, or leave it out completely.
This paper skips past all that, and simply looks at average temperature and GDP. “This is a very significant study,” says Jonathan Harris, economist from Tufts University. “It’s based on real data from 1960 to 2010, not just hypothetical projections.”
Their verdict on how climate change will affect the global economy? “Overall economic production would fall by about 23 percent by 2100 if climate keeps changing under the current models,” says Miguel. That is a huge pile of money that never gets made; the deficit shared between countries both rich and poor.
Some argue that the first world will buffer itself against climate change with technological innovations—air conditioning is credited with saving the American South’s economy, and agricultural companies are already breeding heat resistant crops. But historically—and based on this analysis—that hasn’t been and won’t be true. “If you look back to the 1960s to now, any subset of time between now and then shows a consistent pattern of temperature correlating to GDP,” says Matthias Ruth, economist at Northeastern University. Which means that so far, innovation hasn’t done squat. “And as climate continues to change, keeping pace becomes more difficult, and we will fall ever more behind,” says Ruth.
This study put an even greater burden curbing international emissions. The world still has time to build a less dire future: The upcoming Paris emissions talks seem like the best time and place for a global wheel yank. But right now, the science is looking pretty dismal.

Climate Change Slams Global Economy, Study From Stanford And Berkeley Shows

Fairfax - Eric Roston

Without a track record of adapting to warmer temperatures, signs are we are setting ourselves up for suffering. Photo: NASA

Climate change could cause 10 times as much damage to the global economy as previously estimated, slashing output by as much as 23 per cent by the end of the century, a new research paper from US universities Stanford and Berkeley finds.
Looking at 166 countries between 1960 and 2010, the researchers identified an optimal average annual temperature that coincides with peak productivity. It's 13 degrees celsius, or approximately the climate of San Francisco's bay area (Sydney's mean temperature last year was 19.3 degrees).
Climate change could cause 10 times as much damage to the global economy as previously estimated, slashing output by as much as 23 per cent by the end of the century, a new research paper from US universities Stanford and Berkeley finds.
Looking at 166 countries between 1960 and 2010, the researchers identified an optimal average annual temperature that coincides with peak productivity. It's 13 degrees celsius, or approximately the climate of San Francisco's bay area (Sydney's mean temperature last year was 19.3 degrees).
Countries in the tropics, already hotter than this optimal temperature, are likely to face the most dramatic economic pain from warming, found the study, published in the latest issue of Nature. Countries at or just past the 13-degree annual average, like the US, China, and Japan, may be increasingly vulnerable to losses as the temperature warms. Northern countries well below the ideal average may see benefits as opportunities open up for agriculture and industry.
But this was the least robust finding. And even if the warming improves the lot of Scandinavia and Canada, such nations may not have many healthy trading partners left as others suffer. Also, higher temperatures in northern countries don't take into account changes in precipitation, more extreme weather, and the many other risks in a warming world.
The authors made a clever end run around the biggest problem at the core of climate science: There's only one Earth. Scientists usually like to run "controls," situations that have identical conditions to the experiment except for the one thing being studied. Unfortunately for climate scientists, there's no second Earth, filled with identical people doing identical things, where greenhouse gas emissions aren't a problem.
So the study looks at national temperature records through time. Instead of studying a warming Nigeria and a control Nigeria, the scientists compared Nigerian economic output in average years with that in warming years.
"If you have a lot of data on a lot of countries in a lot of years, that allows you to start to distinguish the particular role of temperature in economic performance," said Stanford's Marshall Burke, the co-lead author.
Once they calibrated this analysis, the researchers took the second step, applying it to the mostly widely accepted climate change scenarios. They found that if the economies continue to respond to heat the way they have in the past, most of the world is in for a rough ride.

This map shows how higher average annual temperatures from climate change may disproportionately impact economic growth around the world. Illustration: Burke, Hsiang, Miguel; Nature

What they are not doing, Burke said, is making an argument that temperature is necessarily the most important factor driving national economies.
"Climate is not fate," he said. "Countries can do a lot, and there many other factors beyond temperature that matter," such as geography, culture, and governance institutions.
Data from the study may challenge some assumptions made in computer models of climate change and economics. So-called integrated assessment models include calculations of a "damage function," which informs how bad, or benign, various changes might turn out. The damage function suggested by the new data is five to 10 times as high as in commonly used models.
William Nordhaus of Yale is the creator of the Dynamic Integrated Model of Climate and the Economy, probably the most commonly used of the three major models. He has seen the new Nature paper but said he would withhold judgment until the statistical analysis of the data has been tested.
"Their findings are startling," said Trevor Houser, an energy climate expert at the Rhodium Group, a research firm. "In their base-case estimate, the global economic price tag is more than 20 per cent of GDP, several times higher than previous estimates."
If the study holds up, it has the potential to influence policy in a couple of ways.

This graph projects the economic impact of climate change on the world
economy through 2100. There is a 63 per cent likelihood that GDP
will fall more than 10 per cent, a 51 per cent chance it will fall more
than 20 per cent, and 12 percent odds it will fall by more than half,
according to the study.
Illustration:Burke, Hsiang, Miguel; Nature

Rational policymakers typically weigh the costs of climate policy to the economy-carbon taxes, fuel efficiency standards, subsidies-against the projected costs of doing nothing, informed assumptions in the damage function of the climate-economic models. A dramatically higher damage function changes the cost/benefit analysis and makes potential policies that looked expensive yesterday much cheaper by comparison.
Another takeaway from the study is that over the last six decades, economies haven't adapted well to hotter temperatures. "We're optimistic on adaptation and its long-run potential," Burke said. "Looking historically, we don't see a lot of evidence that we're good at that."
A cliché repeated in some scientific circles suggests that there are three possible responses to climate change: mitigation (the word wonks like to use instead of prevention), adaptation, and suffering.
If the new study means our mitigation efforts are even weaker than previously thought, and we don't have a proven track record of adaptation, are we setting ourselves up for suffering? "That's exactly right," Burke said. "That's exactly right."

The Countries Where Global Warming Will Shrink Bank Accounts

PBS NewsHour - Nsikan Akpan

A new study from Stanford pinpoints the best annual temperature for getting the job done.
Photo by H. Armstrong Roberts/ClassicStock/Getty Images

It’s no secret that summer lends itself better to beaches and barbecues than actual work. Yet the instinct to shirk work in hot weather is more than a summer slowdown. It’s a broad phenomena that may cripple some nations as global warming progresses.
A new study from Stanford University has pinpointed the optimal annual temperature for economic productivity, and it’s this: 55.4 degrees Fahrenheit, or 13 degrees Celsius. The researchers show that when the climate exceeds this temperature, the country’s economic output drops precipitously. Based on their model published today in the journal Nature, this pattern has held steady for more than 150 countries, affecting both rich and poor, for more than half a century.
If global warming isn’t checked, the team expects average global incomes will be slashed by a quarter by 2100. So whether you’re an Indonesian rice farmer baking in the hot sun or a tech jockey sitting in a cool Silicon Valley office, you can expect your economic prosperity to decline.
“The results indicate that societies will need to adapt in ways that are likely to be expensive, or [they will] face even greater damages in terms of lost GDP,” said economist Michael Greenstone of the University of Chicago, who wasn’t involved in the project.
Stanford economist Marshall Burke and his colleagues created this new projection for the future by treating 166 countries like patients getting regular health checkups.
The team isolated the annual temperatures of each country from 1960 to 2010, and then looked at how that country’s economy performed during each of those years. By comparing warm years to normal years, the team was able to chart how individual economies respond to temperature.

A prediction for how gross domestic product (GDP) will change across the globe by 2100. Colder countries, like Canada, will see an economic boost with climate change, while most tropical nations will witness a drop. This model assumes a “business as usual” global warming scenario, wherein unmitigated climate changes raises temperatures by 4.3 degrees Celsius (8 degrees Fahrenheit) by the end of the century. Photo by Burke M, Hsiang SM and Miguel E., Nature, 2015.

Even when accounting for cultural differences, technological innovations, political upheavals, and economic atom bombs like global recessions, these researchers found an optimal temperature — again, 55.4 degrees Fahrenheit — that, in Burke’s words, “is really good at producing stuff around the world.”
“What we see is it matters less if you’re rich or poor now. It matters more if your [annual] average temperature is hot or cold,” Burke said. “If your country’s temperature is cooler than [55 degrees Fahrenheit], then global warming might help you. If your average temperature is hotter, a little bit of warming might hurt you.”
On a small scale, it’s easy to see how temperatures could impair industries like outdoor construction or agriculture. A drought during a growing season can wipe out crops, whether you’re a midwestern farmer in the U.S. or in Sub Saharan Africa.
But by examining the macroeconomics of climate change, the findings by Burke and his companions support a budding phenomena wherein even white collar jobs in air-conditioned offices will feel the burn of global warming. Prior research in India, for instance, suggests that worker productivity in textile mills drops by “1 to 3 percent per degree Celsius,” despite limited heat stress in the factories. Meanwhile, automobile assembly lines in the U.S. slow down when temperatures outside become too hot.

Photo by moodboard/via Getty Images

“We are already experiencing the economic impacts of climate change — heatwaves, for example, are increasing health costs and employee absenteeism,” economist Thomas Sterner of the University of Gothenburg wrote in accompanying commentary also published today by Nature.
The explanations for the decline in white-collar industries remain unclear, Burke said. What we do know is society gets a little crazy when it’s hot. Fatal car accidents and violence escalate. The rate of heart attacks spikes. Sleep might also be a factor. Burke’s team is currently looking into how sleep quantity and quality dictate economic output on a broad scale.
“It’s an intuitive idea, and we’re searching for quantitative evidence at the moment,” Burke said. Like an itchy, uncomfortable sweater, global warming might simply aggravate society by building collective stress among groups of people.
Until today, the conventional wisdom was that the economic burden of global warming would primarily be felt by poor nations. A seminal study in 2008 drew the relationship between temperature and economic output as a straight line. “The higher temperature, the bigger the costs,” Sterner writes, which meant that low-income nations would be burdened heavily in the future, given most reside in warm climates.

Cornfields during a drought in Tanzania. A 2012 study from MIT predicts that Sub Saharan Africa will witness a decline in the yields of its most common crops over the next century. Photo by Dennis K. Johnson/via Getty Images

Sterner writes that by not assuming a linear relationship, the new model from Burke’s team paints a more accurate picture. It can account for nuanced, micro-level responses between economic productivity and temperature.
As a country’s average temperature gets hotter and extends further past the 55-degree Fahrenheit threshold in Burke’s model, economic productivity fares worse. Poor countries would still suffer the brunt of unmitigated climate change over the next century, but rich countries take a hit too. The annual temperatures for nations like China and the U.S. already hover around the 55 degree-Fahrenheit cliff, so they might witness Overall, 77 percent of the countries surveyed could be poorer by 2100 due simply to global warming.

Temperature effects on GDP over time for nine regions. Black lines are projections using point estimates. Red shaded area is 95% confidence interval, colour saturation indicates estimated likelihood an income trajectory passes through a value. Photo by Burke M, Hsiang SM and Miguel E., Nature, 2015.

“All told, these estimates equate to much larger economic losses than most leading models suggest…,” Sterner writes. “ The current leading models, referred to as integrated assessment models (IAMs), are already being used as a basis for policy. In the United States, there have been considerable battles, even in Congress, concerning the ‘social cost of carbon’, which is based on the three most prominent IAMs.”
Burke’s study argues that Congress and other policy agencies have based their predictions on the social costs of global warming and carbon pollution on estimates that are off by several hundred percent.
“[This study] is part of a growing literature suggesting that climate change is more harmful than current models indicate,” Greenstone said.