"Climate outlook may be worse than feared"

Nothing new here except that a small amount of sanitised truth may be seeping into the proceedings.

Interesting idea that the earth itself might undermine a Paris climate agreement.

How inconvenient!

Tim Groser and Paula Bennett (once she's learnt what the climate is) will be seething.

Enough to turn someone to drink.

Scientists just pointed out how the Earth itself could undermine a Paris climate agreement

Secretary of State John F. Kerry, center right, delivers a speech as U.N. Secretary General Ban Ki-moon, center left, looks on during the Caring for Climate Business Forum event as part of the COP 21 United Nations conference on climate change, Tuesday Dec. 8, 2015, in Le Bourget, on the outskirts of Paris. (Mandel Ngan/Pool Photo via AP)

Washington Post,

9 December, 2015

PARIS — With only three days left, tensions here are rising as countries race to resolve outstanding differences and forge an agreement that — hopefully — will set the planet on a path to avoiding the worst consequences of climate change.

The goal is an agreement that would set the world on a path to limit warming to below 2 degrees Celsius, or perhaps even 1.5 degrees Celsius, above pre-industrial levels. But at a news conference here at the Le Bourget conference center Wednesday morning, scientists pointed out a factor that could make hitting these targets quite a lot harder.

It’s called permafrost.

As the planet warms, this frozen northern soil is going to continue to thaw — and as it thaws, it’s going to release carbon dioxide and methane into the air. A lot of it, it turns out. Potentially enough to really throw off the carbon budgets that have been calculated in order to determine the maximum emissions that we can release and still have a good chance of keeping warming to 2 C or below it.

In particular, Susan Natali of the Woods Hole Research Center explained Wednesday that with a very high level of warming, permafrost emissions this century could be quite large indeed.

Natali used numbers from the 2013 report of the United Nations’ Intergovernmental Panel on Climate Change, which found that humans can only emit about 275 more gigatons, or billion tons, of carbon (about 1,000 gigatons of carbon dioxide, which has a greater molecular weight) to have a greater than 66 percent chance of limiting warming to 2 degrees C.

But out of that limited budget, she said, permafrost emissions could take up some 150 of those gigatons (or about 550 gigatons of carbon dioxide).

“That’s on par with current U.S. rates of emission,” Natali said, which are about 1.4 gigatons of carbon per year. “So we’re talking about another emitting region that’s currently not included in our emissions scenarios.”

Fortunately, even though they’re not considered to be strong enough, the current national pledges to limit global warming appear to have taken the world off a truly high emissions path. These pledges, or “intended nationally determined contributions,” could potentially limit warming to 2.7 degrees Celsius, according to the United Nations.

But in an interview, Natali and her Woods Hole colleague and fellow permafrost expert Max Holmes explained that even for lower warming scenarios like this, permafrost could emit 50 gigatons of carbon (or about 180 gigatons of carbon dioxide) in this century. This is because under lower warming scenarios, only about 30 percent, rather than about 70 percent, of surface layer permafrost is expected to thaw.

In this Aug. 10, 2009 photo, a hill of permafrost  “slumping” from global warming near the remote, boggy fringe of North America, 2,200 kilometers (1,400 miles) from the North Pole.(AP Photo/Rick Bowmer)

Another 50 gigatons out of a 275 gigaton carbon budget — or, another 180 gigatons out of a 1,000 gigaton carbon dioxide budget — would significantly constrain how much the world could emit and still have a strong chance of keeping warming below 2 degrees Celsius.

Another prominent research institute, the U.K. Met Office’s Hadley Center, also recently released an assessment of how potential permafrost emissions could complicate attempts to limit global warming, and came up with numbers that are, if anything, potentially even worse. As the center put it:

The feedbacks from wetlands and permafrost regions can be combined with other known processes to determine their greenhouse gas input into the atmosphere. For a global average temperature rise of 2 °C, this reduces the cumulative emissions that can be released by human actions by around 100GtC (360 GtCO2 ) in the most pessimistic simulation. This corresponds to about 10 years of anthropogenic emissions at the current rate.

These numbers can’t be directly compared with the Woods Hole numbers, however, due to the inclusion of wetlands above.

And Natali and Holmes also noted that permafrost emissions don’t end at 2100 — they are expected to continue after that and even get worse. “Most of the release will happen after 2100,” said Natali.

That’s a big problem because the global carbon budget is fixed, and after it is exceeded there can be zero further emissions. Because carbon dioxide lasts so long in the atmosphere, you don’t get to start with a fresh budget in the next century. So permafrost emissions beyond 2100 would also have to be taken into account, and would restrict the budget even further.

Permafrost is a potential carbon bomb because over thousands of years, dead plant life has been slowly swallowed up by the soil but has not decomposed. Plants pull carbon out of the atmosphere as they grow, but release it again when they die and decompose. As permafrost warms and thaws, microbes will have more ability to break down the plant life it contains, which is what will trigger a steady stream of emissions.

“It’s just like you put celery in your freezer and then you turn your freezer into a refrigerator, and it starts to rot,” says Woods Hole’s Max Holmes.

Many people are confused about permafrost, and think when they first hear about it that it is going to release methane, not carbon dioxide, in gigantic explosions. Actually, that’s confusing frozen subsea methane hydrates — which may or may not be destabilized by global warming, but in any case are a separate issue — with permafrost on land.

The latter will lose carbon slowly, as thaw enables microbial processes that lead to decomposition. This will release both carbon dioxide and also some methane. There won’t be any explosion, says Natali — but as the numbers above show, it could still be dramatically significant to the total global carbon picture.

The news about permafrost has been building in recent years, but it is still a relatively new area of scientific inquiry and one where there is much uncertainty. Thus, even as negotiators in Paris appear to be amping up their ambition and are even talking more about trying to limit global warming to 1.5 degrees C, there may be another wild card they have to contend with.

On Tuesday, Secretary of State John F. Kerry called the Paris climate meeting the “demarcation point where we begin to get the job done to save the planet.” Alas, scientists are learning that the planet itself may not cooperate.

Climate outlook may be worse than feared, global study suggests

A composite image of the Western hemisphere of the Earth. Credit: NASA

Phys.org,

9 December, 2015

As world leaders hold climate talks in Paris, research shows that land surface temperatures may rise by an average of almost 8C by 2100, if significant efforts are not made to counteract climate change.

Such a rise would have a devastating impact on life on Earth. It would place billions of people at risk fromextreme temperatures, flooding, regional drought, and food shortages.

The study calculated the likely effect of increasing atmospheric levels of greenhouse gases above pre-industrialisation amounts. It finds that if emissions continue to grow at current rates, with no significant action taken by society, then by 2100 global land temperatures will have increased by 7.9C, compared with 1750.

This finding lies at the very uppermost range of temperature rise as calculated by the Intergovernmental Panel on Climate Change. It also breaches the United Nations' safe limit of 2C, beyond which the UN says dangerous climate change can be expected.

Research at the University of Edinburgh first created a simple algorithm to determine the key factors shaping climate change and then estimated their likely impact on the world's land and ocean temperatures. The method is more direct and straightforward than that used by the IPCC, which uses sophisticated, but more opaque, computer models.

The study was based on historical temperatures and emissions data. It accounted for atmospheric pollution effects that have been cooling Earth by reflecting sunlight into space, and for the slow response time of the ocean.

Its findings, published in Earth and Environmental Transactions of the Royal Society of Edinburgh, may also help resolve debate over temporary slow-downs in temperature rise.

Professor Roy Thompson, of the University of Edinburgh's School of GeoSciences, who carried out the study, said: "Estimates vary over the impacts of climate change. But what is now clear is that society needs to take firm, speedy action to minimise climate damage."