Climate change: Soot's role underestimated

 

 
The burning of wood is a major source of black carbon the world over.
 

Black carbon, or soot, is making a much larger contribution to global warming than previously recognised, according to research.

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 is 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,"

The researchers say black carbon emissions in Europe and North America have

Greenhouse gases in the atmosphere hit a new record high in 2011, the World Meteorological Organization has said.

 
The cost of damage from extreme weather events is projected to increase in the future.
 

The effects of climate change are already evident in Europe and the situation is set to get worse, the European

Environment Agency has warned.

In a report, the agency says the past decade in Europe has been the warmest on record.

It adds that the cost of damage caused by extreme weather events is rising,

and the continent is set to become more vulnerable in the future.

The findings have been published ahead of next week's UN climate conference.

They join a UN Environment Programme report also released on Wednesday showing

dangerous growth in the "emissions gap" - the difference between current carbon

emission levels and those needed to avert climate change.

"Every indicator we have in terms of giving us an early warning of climate

change and increasing vulnerability is giving us a very strong signal," observed

EEA executive director Jacqueline McGlade.

"It is across the board, it is not just global temperatures," she told BBC News.

"It is in human health aspects, in forests, sea levels, agriculture,

biodiversity - the signals are coming in from right across the environment."

Climate change 'may shrink fish'

 

 
Fish body size is related to the water's temperature and oxygen levels, says the team
 

Fish species are expected to shrink

in size by up to 24% because of global warming, say scientists.

Researchers modelled the impact of rising temperatures on more than 600

species between 2001 and 2050.

Warmer waters could decrease ocean oxygen levels and significantly reduce

fish body weight.

The scientists argue that failure to control greenhouse gas emissions will

have a greater impact on marine ecosystems than previously thought.

Previous research has suggested that changing ocean temperatures would impact

both the distribution and the reproductive abilities of many species of fish.

This new work suggests that fish size would also be heavily impacted.

The researchers built a model to see how fish would react to lower levels of

oxygen in the water. They used data from one of the higher emissions

scenarios developed by the Intergovernmental Panel on Climate Change (IPCC).

Warming the fish

Although this data projects relatively small changes in temperatures at the

bottom of the oceans, the resulting impacts on fish body size are "unexpectedly

large" according to the paper.