Soot's role in warming underestimated

Matt McGrath in BBC News: New research says that black carbon, or soot, is making a much larger contribution to global warming than previously recognised. Scientists say that particles from diesel engines and wood burning could be having twice as much warming effect as assessed in past estimates.

They say it ranks second only to carbon dioxide as the most important climate warming agent. The research has been published in the Journal of Geophysical Research-Atmospheres.

Black carbon aerosols have been known to warm the atmosphere for many years by absorbing sunlight. They also speed the melting of ice and snow. This new study concludes the dark particles are having a warming effect approximately two thirds that of carbon dioxide, and greater than methane.

"The large conclusion is that forcing due to black carbon in the atmosphere is larger," lead author Sarah Doherty told BBC News. "The value the IPCC gave in their 4th assessment report in 2007 is half of what we are presenting in this report - it's a little bit shocking,"...

An open wood fire, shot by Edoddridge, Wikimedia Commons, under the Creative Commons Attribution-Share Alike 3.0 Unported license

Global warming has increased monthly heat records by a factor of five

A press release from the Potsdam Institute for Climate Impacts Research: Monthly temperature extremes have become much more frequent, as measurements from around the world indicate. On average, there are now five times as many record-breaking hot months worldwide than could be expected without long-term global warming, shows a study now published in Climatic Change. In parts of Europe, Africa and southern Asia the number of monthly records has increased even by a factor of ten. 80 percent of observed monthly records would not have occurred without human influence on climate, concludes the authors-team of the Potsdam Institute for Climate Impact Research (PIK) and the Complutense University of Madrid.

“The last decade brought unprecedented heat waves; for instance in the US in 2012, in Russia in 2010, in Australia in 2009, and in Europe in 2003,” lead-author Dim Coumou says. “Heat extremes are causing many deaths, major forest fires, and harvest losses – societies and ecosystems are not adapted to ever new record-breaking temperatures.” The new study relies on 131 years of monthly temperature data for more than 12.000 grid points around the world, provided by NASA. Comprehensive analysis reveals the increase in records.

The researchers developed a robust statistical model that explains the surge in the number of records to be a consequence of the long-term global warming trend. That surge has been particularly steep over the last 40 years, due to a steep global-warming trend over this period. Superimposed on this long-term rise, the data show the effect of natural variability, with especially high numbers of heat records during years with El Niño events. This natural variability, however, does not explain the overall development of record events, found the researchers.

If global warming continues, the study projects that the number of new monthly records will be 12 times as high in 30 years as it would be without climate change. “Now this doesn’t mean there will be 12 times more hot summers in Europe than today – it actually is worse,“ Coumou points out. For the new records set in the 2040s will not just be hot by today’s standards. “To count as new records, they actually have to beat heat records set in the 2020s and 2030s, which will already be hotter than anything we have experienced to date,” explains Coumou. “And this is just the global average – in some continental regions, the increase in new records will be even greater.”....

Record-breaking hot months have become much more frequent. (For full graphic see Fig. 4 in the study) Graphic: PIK

2012 was warmest and second most extreme year on record for the contiguous US

NOAA: 2012 was a historic year for extreme weather that included drought, wildfires, hurricanes and storms; however, tornado activity was below average

2012 marked the warmest year on record for the contiguous United States with the year consisting of a record warm spring, second warmest summer, fourth warmest winter and a warmer-than-average autumn. The average temperature for 2012 was 55.3°F, 3.2°F above the 20th century average, and 1.0°F above 1998, the previous warmest year.

The average precipitation total for the contiguous U.S. for 2012 was 26.57 inches, 2.57 inches below average, making it the 15th driest year on record for the nation. At its peak in July, the drought of 2012 engulfed 61 percent of the nation with the Mountain West, Great Plains, and Midwest experiencing the most intense drought conditions. The dry conditions proved ideal for wildfires in the West, charring 9.2 million acres — the third highest on record.

The U.S. Climate Extremes Index indicated that 2012 was the second most extreme year on record for the nation. The index, which evaluates extremes in temperature and precipitation, as well as landfalling tropical cyclones, was nearly twice the average value and second only to 1998. To date, 2012 has seen 11 disasters that have reached the $1 billion threshold in losses, to include Sandy, Isaac, and tornado outbreaks experienced in the Great Plains, Texas and Southeast/Ohio Valley....

Temperatures to rise by six degrees in Middle East countries

Laurence Caramel in the Guardian (UK): Countries in the Middle East and north Africa will be among those hardest hit by global warming, unless the upward trend for greenhouse gas emissions can be checked, the World Bank warned last month at the Doha climate change conference.

There will be lower rainfall, higher temperatures and continuing desertification, said Rachel Kyte, World Bank vice-president for sustainable development, during her presentation of the report on Adaptation to a Changing Climate in the Arab Countries.

According to the forecasts, average temperatures could rise by 3C between now and 2050. But night temperatures in city centres could increase by double that figure. The report notes that over the last three decades 50 million people have been affected by climate disasters. Severe flooding is now a recurrent event. But the increasing scarcity of water resources is the biggest challenge for countries in the region, which already have some of the lowest per capita reserves in the world.

Kuwait and Qatar depend on desalination plants for almost 40% of their needs. With demand for water forecast to increase by 60% over the next 30 years, due to population growth and changing ways of life, the World Bank fears there is a high risk of shortages and conflict. Measures to adapt to climate change are still limited, even if a regional strategy for reducing the risks of natural disasters has been adopted.

The lack of reliable data is a stumbling block for any preventive measures. The launch of a research centre, announced by Qatar last month, could help remedy this situation. Funded by the Qatar Foundation, in partnership with the Potsdam Institute, the centre will focus on the impact of climate change on countries in the Gulf....

A natural arch in Jebel Kharaz, Jordan, shot by Etan J. Tal, Wikimedia Commons, under the Creative Commons Attribution 3.0 Unported license