Climate change news - 12/04/2014

"Now, The New York Times reports, the negotiators’ objective is to stave off atmospheric warming of 4 to 10 degrees Fareinheit, or roughly 2.2 to 5.6 degrees Celsius, by the end of the century, at which point, experts say, Earth may “become increasingly uninhabitable.” 

So there you have it 2 degrees C has been chucked under the bus and we are 'hoping' for 5C. At 5C our global food production will have collapsed and we have no ice in the planets thermometer. 

Way before 5C we have massive amounts of methane ejected into the atmosphere to unleash more positive feedback loops. 

Minor qualification to the issue of China and the U.S. agreeing to reductions. 

They have all made these bold statements before and never met them. 

Peru and Paris will go the same way as COP-15.

--Kevin Hester

At Lima Climate Talks, 2-Degree Warming Limit Is a Thing of the Past

Newsweek,

1 December, 2014

We are now officially in arm’s reach of “dangerous” levels of global warming.

United Nations negotiators are meeting this week in Peru to forge a much-anticipated draft agreement to curb global climate change. They’re brimming with optimism after the recent climate agreement between the U.S. and China, which had eluded negotiators for years.

But amid the hope is a much darker reality: Years of stalled talks and baby steps toward action have all but ensured that we will pass the previous do-not-pass benchmark of 2 degrees Celsius (3.6 degrees Fahrenheit) of warming by 2100. Now, The New York Times reports, the negotiators’ objective is to stave off atmospheric warming of 4 to 10 degrees Fahrenheit, or roughly 2.2 to 5.6 degrees Celsius, by the end of the century, at which point, experts say, Earth may “become increasingly uninhabitable.”

Scientists say moving into that range of warming would result in a significantly different world. For example, four degrees Celsius of warming is enough to melt most or all of the world’s ice. As climatologist and former NASA Goddard Institute for Space Studies chief James Hansen put it in a paper published in the journal Nature last year:

“Four degrees of warming would be enough to melt all the ice.... You would have a tremendously chaotic situation as you moved away from our current climate towards another one. That’s a different planet. You wouldn’t recognise it.... We are on the verge of creating climate chaos if we don’t begin to reduce emissions rapidly.”

Steven Sherwood, a professor at the University of New South Wales, in Australia, and author of another study looking at the implications of four-degree warming, came to a similar conclusion.

“4C would likely be catastrophic rather than simply dangerous,” Sherwood told the Guardian. “For example, it would make life difficult, if not impossible, in much of the tropics, and would guarantee the eventual melting of the Greenland ice sheet and some of the Antarctic ice sheet.”

The volume of water in the Greenland and Antarctic ice sheets alone would raise sea levels by 65 meters, or roughly 213 feet, if released. For comparison, the Statue of Liberty is 150 feet tall. Coastal regions and island nations would all but disappear. Long before then, freshwater sources would become inundated by saltwater.

The U.N. released a report in November that concluded 2 degrees of warming could be avoided only if global emissions peak within the next 10 years and then plummet sharply, going down by half by 2050. A deal of that magnitude is not even on the table. In fact, the agreement being drafted in Lima this week will not be enacted until 2020.

Meanwhile, officials at the U.S. National Oceanic and Atmospheric Administration report that 2014 will likely be the warmest year on record. Welcome to a very different type of climate discussion.

Correction: This article has been updated to reflect the fact that the 4-10 degree warming range cited by the New York Times was in Fahrenheit, not Celsius.

CO2 warming effects felt just a decade after being emitted

It takes just 10 years for a single emission of carbon dioxide (CO2) to have its maximum warming effects on the Earth.

IOP,

3 December, 2014

This is according to researchers at the Carnegie Institute for Science who have dispelled a common misconception that the main warming effects from a CO2 emission will not be felt for several decades.

The results, which have been published today, 3 December, in IOP Publishing’s journal Environmental Research Letters, also confirm that warming can persist for more than a century and suggest that the benefits from emission reductions will be felt by those who have worked to curb the emissions and not just future generations.

Some of these benefits would be the avoidance of extreme weather events, such as droughts, heatwaves and flooding, which are expected to increase concurrently with the change in temperature.

However, some of the bigger climate impacts from warming, such as sea-level rise, melting ice sheets and long-lasting damage to ecosystems, will have a much bigger time lag and may not occur for hundreds or thousands of years later, according to the researchers.

Lead author of the study Dr Katharine Ricke said: “Amazingly, despite many decades of climate science, there has never been a study focused on how long it takes to feel the warming from a particular emission of carbon dioxide, taking carbon-climate uncertainties into consideration.

“A lot of climate scientists may have an intuition about how long it takes to feel the warming from a particular emission of CO2, but that intuition might be a little bit out of sync with our best estimates from today's climate and carbon cycle models.”

To calculate this timeframe, Dr Ricke, alongside Professor Ken Caldeira, combined results from two climate modelling projects.

The researchers combined information about the Earth’s carbon cycle – specifically how quickly the ocean and biosphere took up a large pulse of CO2 into the atmosphere – with information about the Earth’s climate system taken from a group of climate models used in the latest IPCC assessment.

The results showed that the median time between a single CO2 emission and maximum warming was 10.1 years, and reaffirmed that most of the warming persists for more than a century.

The reason for this time lag is because the upper layers of the oceans take longer to heat up than the atmosphere. As the oceans take up more and more heat which causes the overall climate to warm up, the warming effects of CO2 emissions actually begin to diminish as CO2 is eventually removed from the atmosphere. It takes around 10 years for these two competing factors to cancel each other out and for warming to be at a maximum.

“Our results show that people alive today are very likely to benefit from emissions avoided today and that these will not accrue solely to impact future generations,” Dr Ricke continued.

"Our findings should dislodge previous misconceptions about this timeframe that have played a key part in the failure to reach policy consensus.”

From Tuesday 3 December, this paper can be downloaded fromhttp://iopscience.iop.org/1748-9326/9/12/124002/article