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Up to Five Billion Face ‘Entirely New Climate’ by 2050

The mean annual climate of the average location on Earth will slip past the most extreme conditions experienced during the past 150 years and into new territory by between 2047 and 2069, depending on the amount of climate-warming greenhouse gases that are emitted during the next few decades, a new study found. The study, published Wednesday in the journal Nature, used a new index to show for the first time when the climate — which has been warming during the past century in response to manmade pollution and natural variability — will be radically different from average conditions during the 1860-2005 period.

The study shows that tropical areas, which contain the richest diversity of species on the planet as well as some of the poorest countries, will be among the first to see the climate exceed historical limits — in as little as a decade from now — which spells trouble for rainforest ecosystems and nations that have a limited capacity to adapt to rapid climate change.

Map of multi-model mean results for different greenhouse gas concentration scenarios of annual mean surface temperature change in 2081– 2100.
Credit: IPCC Working Group I.

According to the study, conducted by a team from the University of Hawaii, about 1 billion people currently live in areas where the climate will exceed historical bounds of variability by 2050. This number would rise to 5 billion people under a business-as-usual emissions scenario, which is the emissions path the world is currently on.

Even more strikingly, the study found that the oceans, which have absorbed about half of the manmade carbon dioxide (CO2) emissions since the dawn of the industrial revolution 250 years ago, exceeded their historical bounds of pH measurements back in 2008.

In other words, the oceans are now more acidic than they have been since at least 1860.

The study “Provides a new metric of when climate change will lead to an environment that we’ve never seen before,” said author Camilo Mora, a professor at the University of Hawaii at Manoa, in an interview.

“When you look at the information there is a lot of empirical evidence suggesting that indeed we already crossed the threshold of pH variability during the last decade”

In the water, CO2 reacts to form carbonic acid, and over the years, the ocean’s acidity has increased by more than 30 percent because so much of the excess man-made CO2 is being drawn into the water.

This increased acidity changes the balance of other carbon-species in the water, and may have far-reaching ramifications. Some marine species that use a form of carbonate to build their skeletons and shells, like corals and mollusks, may be harmed because the acid formed in the water consumes this carbonate and makes it less accessible to these organisms.

Even with aggressive cuts in greenhouse gas emissions, the study found, the projected near-surface air temperature of the average location on Earth will move beyond historical variability in about 56 years from now. A business-as-usual scenario in which emissions continue on their current upward trajectory would see an unprecedented climate occurring 20 years sooner than that, in 2047.

However, the extra 20 years that emissions cuts would buy time for making emissions cuts and could prove crucial for many species’ survival, Mora said.

Imagine you are on a highway, and you spot an obstacle in the road up ahead, Mora said. “Should you step on the gas, or hit the brake?” Hitting an obstacle at a slower speed will minimize the damage to the car and its occupants, in much the same way as hitting a climate threshold at a slower speed would reduce the ramifications for biological systems, he said. “The speed at which you face that (obstacle) is going to make a huge difference."

The study questions the way climate change is typically framed, which is by looking at the absolute value of the temperature change that is expected to occur in the coming decades. This framing often identifies the Arctic as being ground zero for the most significant and rapid climate change, and overlooks the fact that, while the Arctic has a history of bigger temperature swings, that's not the case in the tropics, where temperatures have historically remained within a narrower range. That makes it easier for a small amount of warming to make a big difference in tropical climate.

For temperature-sensitive tropical species, such as coral reefs, the speed at which climate change occurs can be a more important factor in determining how disruptive climate change will be, even though the total amount of climate change expected in the tropics will be less than in the Far North.

Chart showing the year by which the climate is projected to exceed the range of historical variability, depending on the emissions scenario. "Stabilized emissions" corresponds to a low emissions scenario.
Click to enlarge the image.
Credit: Alyson Kenward, Climate Central. Data from Mora et al.

“The tropics, not the poles, are going to be feeling the effects first,” Mora said. 

Mora said the index he and his team developed aims to address this shortcoming of traditional climate studies. The index used the minimum and maximum temperatures from 1860-2005 to define the bounds of historical climate variability at any given location. The scientists then took projections from 39 climate models for the next century to find the year in which the future temperature will exceed the limits of historical precedents, defining that year as the year of climate departure. When the climate reaches this point, the average temperature of the coolest year at a given location will be greater than the average temperature of its hottest year for the period from 1860 to 2005.

“We analyzed every single model that has been developed so far,” Mora said. “All of that data is telling you something in common, and that is that pretty soon we’re going to be facing unprecedented climate.”

Since many tropical nations are major suppliers of food to global markets, including fish that rely on healthy coral reef ecosystems as well as many other goods and services, there may be ripple effects throughout the global economy despite the longer lag time before the climate of the industrialized nations exceed the bounds of their historical climate, Mora said.

Warming in the tropics, he said, “Will increase the prices of the things that we have to pay here.”

Given that there are considerable uncertainties about future greenhouse gas emissions as well as the precise response of the climate system to those emissions, not to mention the uncertainties inherent in computer modeling, the study should not be taken as offering precise predictions. However, the researchers found low uncertainties associated with the date ranges by which the climate would exceed previous bounds, with greater uncertainties associated with the changes likely to take place in different geographical locations.

Ed Hawkins, a climate scientist at the University of Reading who was not involved in the new study, said the findings build on previously published research about the timing of climate change impacts. “As shown by last month’s latest assessment report by the IPCC, the focus of climate science has moved from whether climate change is happening, to when and where it will be most keenly felt," he said in a statement that was emailed to reporters.

“This kind of work is particularly important as it helps to focus the minds of policy makers about when climate change will start to change our environment. It shows that in many parts of the world, climate change will start to have a major impact in our own lifetimes, not just during those of our children and grandchildren.”

Related Content
Accelerated Warming Driving Arctic Into New, Volatile State
Ocean Acidification Threatens Food Security, Report
Andes' Tropical Glaciers Going Fast, May Soon Be Gone
arming May Increase Tropical Rainfall, Study Shows
NOAA: 2012 Hottest and 2nd-Most Extreme Year on Record


By Eric Peterson (Front Royal, VA 22630)
on October 10th, 2013

“However, the researchers found low uncertainties associated with the date ranges by which the climate would exceed previous bounds”

Comparing models to other models?  That’s a rather narrow definition of uncertainty.  Just because models are in agreement doesn’t mean there is less uncertainty in their results.  That’s because the largest uncertainties lie in factors that are not modeled like cosmic rays, changes in the solar spectrum, small scale weather, etc/

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By john harkness
on October 10th, 2013

Given that:

—much of India (especially the north) is already at or near 30 degree C for wet bulb temperature, and

—35 degrees C wbt is the point at which human (and much other) life becomes impossible, and

—India will exceed historic norms within about 20 years (Sri Lanka, even earlier), according to the chart above…

..Does all this mean that much of the Indian subcontinent and environs will likely become uninhabitable within the next couple decades?

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By Hank Roberts (Lexington VA 24450)
on October 10th, 2013

> the largest uncertainties lie in factors that are not modeled like cosmic rays, changes in the solar spectrum ...

Outdated info—check with your local librarian about how to look this stuff up. 

When I last checked on those (related) factors they were rather well known.  Modeling this decade has trouble mostly with humidity and cloudiness.  Cosmic rays vary with the solar cycle in a known and predictable way that does’t correlate with changes in climate or rain or cloudiness to any significant extent.  The solar spectrum changes slightly over time (fund the satellites and we’ll know more)—more or less ultraviolet at different points in the solar cycle—but not much and not making a detectable change in climate.

Sure the answer could be different next week—science keeps changing—but last year’s or last decade’s claims are way out of date.

If your librarian—or whoever you consider a reliable source—has new facts, tell us who you’re relying on and where the facts can be looked up.

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By Lewis Cleverdon
on October 10th, 2013

Andrew - thanks for this report on the study, which appears to raise as many questions as it answers.

By using as it’s metric the mean date of novel climates’ emergence at diverse locations the study allows the impression of novel climates’ incremental advance, with no mention (being reported) of the increasingly erratic swings from one extreme to another now occurring. (For example, Russia’s unprecedented and prolonged heatwave being followed this year by unprecedented and prolonged floods). This ongoing process of the destabilization of climate, as opposed to the widespread public assumption of an incremental advance of hotter climates, surely poses a very different challenge to any possibilities of adaption, and thus to the date of onset of societally untenable conditions ?

Mora’s observation that: “Since many tropical nations are major suppliers of food to global markets, including fish that rely on healthy coral reef ecosystems as well as many other goods and services, there may be ripple effects throughout the global economy despite the longer lag time before the climate of the industrialized nations exceed the bounds of their historical climate”
- is at odds with studies of the near term scale of impacts on agriculture. “Ripple effects throughout the global economy” is a phrase lacking in urgency and even encouraging complacency when compared to the findings of the 2012 study: “Food Security: Near future projections of the impact of drought in Asia” This study was headed by an IPCC lead author and shows that China, Pakistan and Turkey are the most seriously affected of the region’s major producers of wheat and maize, and is posted at

Quote from the press release:
Research released today shows that within the next 10 years large parts of Asia can expect increased risk of more severe droughts, which will impact regional and possibly even global food security. On average, across Asia, droughts lasting longer than three months will be more than twice as severe in terms of their soil moisture deficit compared to the 1990-2005 period. This is cause for concern as China and India have the world’s largest populations and are Asia’s largest food producers.

Dr Lawrence Jackson, a co-author of the report, said: “Our work surprised us when we saw that the threat to food security was so imminent; the increased risk of severe droughts is only 10 years away for China and India. These are the world’s largest populations and food producers; and, as such, this poses a real threat to food security.”

Since comparable reports are starting to appear for other regions including Southern Africa. Western USA, Brazil, the Mediterranean Basin, etc, and since there has been no theoretical or empirical finding of Asia’s prospects being significantly worse than other regions, it seems reasonable to conclude that without commensurate mitigation we’d probably face the onset of serial global crop failures and consequent geopolitical destabilization during the 2020s. Which implies an utterly different degree of urgency to “ripple effects throughout the global economy” by 2047. So I’m wondering to what extent this new study incorporated the current prognoses for the near-term climatic destabilization of global agriculture ?

Your report of the study’s assessment of the outcome of moderate emissions control (RCP4.5) is very helpful in indicating that this would postpone the proposed average date of onset of novel climates by about 20 years to 2069, but beside choosing not to show the outcomes for RCP2.6, as reported it doesn’t appear to address two factors:
- that the timelag on emissions’ warming being realized would continue the warming and its development of more extreme climates for several decades after 2069,
- and that the exclusion from the calculation of the RCPs of at least six out of the eight major feedbacks that have begun accelerating under 0.8C (including the decline of oceanic sinks’ efficiency) means that RCP4.5 predictably understates both the airborne CO2 concentration and the rate, duration and degree of warming that it would allow.

In light of these two factors, unless the rise of SAT under RCP4.5 from 0.8C to around 2.6C of anthro-warming by 2100 can somehow be shown to halt the feedback’s acceleration and interaction, it must be assumed that continued warming up to and after 2069 would continue to drive the increase of the feedbacks CO2e outputs up to and past the point of their offsetting society’s emissions control.

From this perspective, alongside that of the looming risk of ruinous global crop failures, please could you either describe what I’m missing that precludes these outcomes - (perhaps the manner in which RCP2.6 could resolve these issues?), or alternatively could you outline what could cause the scientific community to acknowledge that, for the global society to be conserved, we are already committed to a degree of warming and climate destabilization that demands the research and deployment of both modes of Geo-E alongside rapid emissions control ? 



P.S.:-  Mora’s remark on the 20yr postponement : “However, the extra 20 years that emissions cuts would buy time for making emissions cuts and could prove crucial for many species’ survival” - perhaps needs clarification ?

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By Eric Peterson (Front Royal, VA 22630)
on October 12th, 2013

Hank, there is work incorporating some solar effects (GCR, spectral changes, etc) into some simple (atmosphere only) models by Haigh and others.  But their work just highlights the fact that it is excluded from all the climate models used by the IPCC.

Your dismissal of cosmic rays echoes the IPCC.  Since cosmic rays are galactic in origin, there’s no reason to expect a good correlation with the solar cycle.  There is some correlation in the short run since the galactic flux changes slowly with a few scattered events.  The connection to clouds is well understood, but the connection from those clouds to climate is obviously variable.  It varies by season and by latitude.

To give just one example, low GCR at high latitudes in summer will cause less low cloudiness and more arctic warmth.  Thus the high solar (low GCR) regime of the late 20th century has led to arctic warming.  That should start to reverse (with some lag due to the warmed ocean) as the solar activity stays low for another decade or two.

As another example, low solar activity is linked to increased meridional flow basically by warming the stratosphere by less ozone destruction.  That relatively uneven warming is linked to blocking patterns, increased meridional flow, increased meridional heat flux and global cooling.  Or in our case a decrease in global warming which is still ongoing due to increased CO2.

None of this is modeled and models are claimed to produce contrary results.  For example, meridional flow is claimed to be a result of arctic amplification.

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By Jim Callahan (Orlando, FL 32801)
on October 13th, 2013

Is there a date for Miami?
According to the map published in the Washington Post blog it looks like Miami is at least a decade earlier than the 2046 date for Orlando and it also looks like Miami is the first city in the U.S. (although logically Key West might be earlier).

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By Crabby (Perth, Western Australia, 6054)
on October 15th, 2013

It might happen! Can we possibly predict the Weather and therefore the Climate in 37 years time.
More pie in the sky till we die by the Big Green Monster. Also if we could get rid of all the GHG
producing Power Stations Worldwide, can we afford to replace it with Renewables? I think not!
Even with energy efficiency measures (the more practical way to “green” the planet), we will have
to get power from somewhere and baseload power can only come from a few sources.

Hydro-electric seems to be the most Cost-Efficient in terms of Dollars spent for Power output I seem to
recall. Solar on rooftops with battery storage for night time power might get individuals off the grid
but would probably cost too much for Billions of people to do it. Wake up people, these green
Charlatans are just after heaps of money to further push the non-sensical green agenda. Good Luck
to All.

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By Jim Macdonald (South Windsor, CT 06074)
on November 5th, 2013

With the climate models in disarray, departing ever further from reality, even with climate sensitivity reduced to around 2C for a doubling of CO2, predictions of what conditions will be like in 2050 are preposterous. We have now had 16 years with no warming and even a little cooling since 2002. The actual climate sensitivity may be closer to 1, as indicated by Prof. Richard Lindzen and others, making the effect of CO2 easily overcome by natural forces, even cloud amounts.

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