Tuesday, November 29, 2011
Report warns of deadly climate change
Monday, November 28, 2011
Research shows that Southern Ocean is warming and freshening
MEDIA RELEASE
The Antarctic Climate and Ecosystems CRC has launched a synopsis of the latest scientific research into changes in the temperature, salinity, acidity and circulation in the Southern Ocean.The Southern Ocean plays a critical role in global and regional climate. More than 90% of the extra heat energy stored by the planet in the past 50 years has been absorbed in the world's oceans, with the Southern Ocean's latitude band storing more heat and CO2 than any other latitude band.
The synopsis, titled Position Analysis: Climate Change and the Southern Ocean, is a plain‐English summary of knowledge in this research area.
The latest research shows:
- The Southern Ocean is warming faster than the average for the global ocean.
- The warming extends to greater depth in the Southern Ocean than it does in low latitudesbecause of the unique ocean currents there that carry heat deep in the ocean. The large amount of heat stored in the ocean makes it expand, raising sea levels.
- These currents also carry large amounts of carbon dioxide into the deep ocean, slowing the rate of climate change. More than 40% of the carbon dioxide released by human activities that ends up stored in the ocean enters through the Southern Ocean.
- The Southern Ocean is getting fresher (lower in salinity). The changes in salinity provide evidence that the global water cycle is becoming more intense, with wet areas becoming wetter and dry areas becoming drier, as expected in a warming climate.
- Freshening is observed in the abyssal waters off Antarctica south of Tasmania, and in the intermediate depth waters that originate in the Southern Ocean.
- New measurements show that even the deepest waters, below 4 km depth, are warming and freshening. This means that even the deepest layers of the ocean can respond to changes in surface climate very quickly.
- The ocean is becoming more acidic, making it more difficult for a wide variety of organisms to build shells, skeletons and reefs.
- Because the effects of ocean acidification are sensitive to temperature, the threshold will be crossed first in the cold waters of the polar regions.
The report was prepared by the ACE CRC Oceans program leader Dr Steve Rintoul and the ACE CRC's Professor Nathan Bindoff, who is a project leader within the Oceans program.
Dr Rintoul said that understanding of the Southern Ocean and its role in the climate system had suffered from a lack of observations. "New technologies are allowing us to really measure the Southern Ocean for the first time, he said.
"The changes we have observed in the temperature, salinity, sea level and carbon concentrations in the Southern Ocean are important because they tell us how and why the climate system is changing," he said. "Because the Southern Ocean affects global and regional climate in profound ways, any changes in the region potentially have widespread consequences."
The CEO of the ACE CRC, Dr Tony Press, said that undertaking research in the Southern Ocean was expensive and logistically complex, making collaboration between organisations, nations and scientific disciplines crucial.
"Given its location and capabilities, Australia should provide leadership in international research efforts in the Southern Ocean," Dr Press said. "Our research in this area is already highly regarded and Australia is strategically placed to make a substantial contribution to understanding climate change in the Southern Ocean."
The Position Analysis underlines the importance of continued investment in the hardware required for ocean observation – this includes robotic instruments (called Argo floats), underwater autonomous vehicles, satellites and instrumentation that can record information from ships and planes.
The Position Analysis defines the Southern Ocean as the area south of 30◦S.
Link to Position Analysis:Climate Change and the Southern Ocean
To:
- arrange interviews with oceanographers Steve Rintoul or Nathan Bindoff
- discuss the policy section of the position analysis with ACE CEO Tony Press
- receive a PDF of the position analysis
please contact:
Miranda Harman
ACE CRC Communications and Media Manager
+61 3 6226‐2265
+419 507 268
Miranda.harman@acecrc.org.au
Wednesday, November 23, 2011
Arctic sea ice loss 'unprecedented', study finds
So-called greenhouse gases may be contributing to the warming, and trends from the last several decades suggest there may soon be an ice-free Arctic in the summer, according to a study published today in the journal Nature.
The ice, which melts every summer before cold weather makes it expand again, shrank this year to its second-smallest size since 1979, covering 4.33 million square kilometers (1.67 million square miles), according to the US National Snow and Ice Data Center. Although previous sea ice declines have occurred at a similar pace, they don't match the extent of the melt, the study authors said.
"This drastic and continuous decrease we've been seeing from the satellites does seem to be anomalous," Christophe Kinnard, a study author and a geographer at the Centro de Estudios Avanzados en Zonas Aridas in La Serena, Chile, said in a telephone interview. "It does point to a continuation of this trend in the future."
The researchers used ice core records, tree ring data, lake sediment and historical evidence to reconstruct the amount of Arctic cover. The thickness and extent of sea ice have declined dramatically over the last 30 years, the researchers said.
Arctic sea ice influences the global climate, since 80 percent of the sunlight that strikes it is reflected back to space. When the ice melts in the summer, it exposes the ocean surface, which absorbs about 90 percent of the light, heating the water, according to the National Snow and Ice Data Center. That influences climate patterns.
"You increase the radiation that's absorbed by the oceans, that's one of the strongest climate feedback mechanisms," Kinnard said. "The more sea ice you lose, the more energy you get in the ocean, which warms the atmosphere."
Monday, November 21, 2011
Greenhouse Gas Concentrations Continue Climbing
Friday, November 18, 2011
IPCC expected to confirm link between climate change and extreme weather Report likely to conclude that man-made emissions are increasing the frequency of storms, floods and droughts
The final details are being fought over by governments, as the "summary for policymakers" of the report has to be agreed in full by every nation that chooses to be involved. But the conclusions are expected to be that emissions from human activities are increasing the frequency of extreme weather events. In particular, there are likely to be many more heatwaves, droughts and changes in rainfall patterns.
Jake Schmidt of the US-based Natural Resources Defense Council said: "This report should be a wake-up call to those that believe that climate change is some distant issue that might impact someone else. The report documents that extreme weather is happening now and that global warming will bring very dangerous events in the future. From the report you can see that extreme weather will impact everyone in one way or another. This is a window into the future if our political response doesn't change quickly."
Jake Schmidt of the US-based Natural Resources Defense Council said: "This report should be a wake-up call to those that believe that climate change is some distant issue that might impact someone else. The report documents that extreme weather is happening now and that global warming will bring very dangerous events in the future. From the report you can see that extreme weather will impact everyone in one way or another. This is a window into the future if our political response doesn't change quickly."
This special report - one of only two that the IPCC is publishing before its 2014 comprehensive assessment of the state of climate change science - is particularly controversial as it deals with the relationship between man-made climate change and damaging events such as storms, floods and droughts. Some climate change sceptics and scientists cast doubt on whether the observed increase in extreme weather events can be attributed directly to human actions, or whether much of it is due to natural variability in the weather.
The IPCC, a body of the world's leading climate scientists convened by the United Nations, is likely to conclude that extreme weather can be linked to man-made climate change, but that individual weather events can at present only rarely be linked directly to global warming.
The Red Cross warned that disaster agencies were already dealing with the effects of climate change in vulnerable countries across the world. "The findings of this report certainly tally with what the Red Cross Movement is seeing, which is a rise in the number of weather-related emergencies around the world," said Maarten van Aalst, director of the Red Cross / Red Crescent Climate Centre and coordinating lead author of the IPCC report. "We are committed to responding to disasters whenever and wherever they happen, but we have to recognise that if the number of disasters continues to increase, the current model we have for responding to them is simply impossible to sustain."
Insurers are also worried. Mark Way, of the insurance giant Swiss Re, told the Guardian that the massive increase in insurance claims was causing serious concern. He said that between 1970 and 1989, the insurance industry globally had paid out an average of $5bn a year in weather-related claims, but that this had increased enormously to $27bn a year. Although not all of this was attributable to climate change - increasing population, urbanisation and prosperity also play a major part - he said insurers wanted governments to get to grips with the effects of climate change in order to prepare for likely damage and tackle the causes of global warming.