These posts are intended to share information and ideas about climate change and hence act as an open thread. Again I do not want to spend time in comments rehashing whether human activity causes climate change.
This edition contains items, exclusively, I think, in climate science and impacts. The thread is meant to function also as a roundtable to share information and ideas.
1. Climate change picked the crops we eat today
The New Scientist carries a story about how some cereals we know today were changed by the climate as we came out of the last ice age. Researchers at the University of Sheffield, UK took seeds of precursors of modern wheat and barley found with human remains in a 23,000-year-old archaeological site in Israel. They grew these together with four wild grass species that aren’t eaten today, but were also known to grow in the region at that time, and grew them under conditions replicating levels of CO2 then and also the higher levels when farming first arose 10,000 years ago.
All the plants grew larger under the higher levels of CO2, but the relatives of wheat and barley grew twice as large and produced double the seeds. This suggests the species are especially sensitive to high levels of CO2, making them the best choice for cultivation after the last ice age.
The team plan to look at whether other food staples around the world are similarly affected by elevated CO2 levels, for example millet grown in Asia and maize in North America. They also plan to compare the effects of CO2 on legumes such as peas.
2. Glass Sponges Move In As Antarctic Ice Shelves Melt
Scientists have been surprised by the rapid growth of glass sponges on the continental shelves newly exposed by the breakup of ice shelves in Antarctica. Things happen slowly down there with the growing season measured in weeks rather than months.
Glass sponges provide habitat for many other organisms, thus fostering diversity. The larger implication is that we simply can’t predict how ecosystems are going to react to climate change.
3. A question of risk
Dana Nuccitelli asks whether climate change represents humanity’s greatest-ever risk management failure.
Climate change presents an enormous global risk, not in an improbable one-in-a-million case, but rather in the most likely scenario. From a risk management perspective, our choice could not be clearer. We should be taking serious steps to reduce our impact on the climate via fossil fuel consumption and associated greenhouse gas emissions. But we’re not.
Thanks to Ootz for the heads-up.
4. Zero energy, carbon neutral Global Change Institute officially opened
The University of Queensland’s zero energy, carbon neutral Global Change Institute has officially opened.
Costing $32 million the building was made possible by a $15 million donation from UQ alumnus and philanthropist Graeme Wood.
The researchers in the building will be able to assess to assess the building systems and optimal comfort conditions in low-energy buildings for the sub-tropics.
“The Global Change Institute has created a hub where new ideas about sustainability and global climate change are expressed, debated, investigated and reported,” Professor Høj said.
“This building is the ideal home for the Institute’s game-changing research into clean energy, healthy oceans, food security and climate change.
5. IPCC leaks
Leaks from the fifth IPCC report due out from late September, suggest that the view on AGW will be firmed up to the 95% confidence level.
The IPCC is right to say it would be premature and misleading to draw conclusions from the leaked draft.Governments and scientists have to clear the final draft which needs the consensus of all parties. The 95% figure is exactly the sort of figure that could be watered down in the final screening.
The ABC has confirmed the latest draft report also predicts that sea levels will rise by between 29 and 82cm by the end of the century, with scientists fairly confident that will be the upper limit.
If so I’d suggest this would remain, as it’s below what scientists have been suggesting in recent years. Nevertheless in the next few decades the likely effect will be an increase in storms and floods.
The authors looked at present and future flood losses in 136 of the world’s largest coastal cities.
Average global flood losses in 2005 were around $6.6 billion, but the study suggests that could increase to $70 billion by 2050.
That gives plenty cause for concern.
6. Canyon discovered under Greenland ice
A canyon almost twice as long as the grand canyon has been discovered under the Greenland ice sheet.
Greenland, unlike Antarctica, has no lakes under its ice sheet. Channels such as the one discovered drain meltwater away into the sea. The effect is that glaciers are not speeding up as much as would otherwise be expected, thus delaying ice sheet decay.
7. Recent global-warming hiatus tied to equatorial Pacific surface cooling
Yu Kosaka and Shang-Ping Xie of the Scripps Institution of Oceanography have developed a sophisticated computer climate model which includes the surface temperatures of the eastern tropical Pacific, some 8.2% of the planet’s surface. This has produced a better match between what had been expected from radiative forcing and observations of what actually happened in the socalled ‘warming hiatus’ of the last 15 years. It accounts for most of the difference in these two lines:
In the following image the new model (red line) better tracks what happened (black) compared with the old model (purple). Hope that’s not oversimplifying.
Trouble is the new model doesn’t tell you what’s going to happen next. The Pacific ocean temperatures added to the new model are associated with natural decadal changes which incorporate El Niño and La Niña. We are no further in front as to why these changes happen.
Also the study doesn’t address where the heat is going from additional radiative forcing. This is better captured by earlier work done by Meehl and others. Essentially heat is moving around between the layers of the ocean and some of the additional radiated heat coming in ends up in the deep.
For a succinct story the paper abstract is best. Then perhaps Roz Pidcock at The Carbon Brief. Andrew Freedman at Climate Central has comments from a range of scientists. There’s more at The Guardian blog and article.
8. East Antarctic ice sheet ‘vulnerable’ to temperature changes
Recent work on the East Antarctica ice sheet has shown that the glaciers are more responsive to climate change than previously thought. This brings home to me the level of uncertainty there is in the processes of ice sheet decay in response to warming. To me we just don’t know enough to be certain what the near-term effects will be (say the next couple of centuries) or the equilibrium balance for a particular global temperature rise.
9. Sea level hiatus
During 2010 to 2011 there was massive rain in Australia which coincided with a sea level drop of 7mm, as against a trend rise of 3.2mm pa. Here is the graph:
Seems they are related. Much of the water flowed inland. Nevertheless sea level has now taken off by 10mm pa.
Brisbane Times has an article with lots of pics.
Scientists are still somewhat befuddled because the New Scientist report says that it was SE Asia and South America as well as Australia, but the water on land only accounted for 3.75mm. Still some splaining needed.
10. Sea level rise taped
Finally a new paper (see Anders Levermann at The Conversation and RealClimate) has found that sea level rise will be about 2.3 metres for each degree of temperature rise. When, they don’t know, but they reckon not all this century, but no longer than 2000 years.
This is at huge variance with the estimates by Hansen and others. The following graph always made sense to me in terms of what has happened in the past:
Coming out of the last ice age sea level rose over 20m per degree. With the two ice sheets left that should drop to 15m or so.
That makes sense, the new information doesn’t. I haven’t had time to look at the detail but they must have good reasons why those two great lumps of ice are not easily destroyed.