Siberian permafrost thaw warning sparked by cave data

The caves record changing conditions over hundreds of thousands of years

Evidence from Siberian caves suggests that a global temperature rise of 1.5C could see permafrost thaw over a large area of Siberia.

A study shows that more than a trillion tonnes of the greenhouse gases CO2 and methane could be released into the atmosphere as a result. An international team has published details in the journal Science. The evidence comes from analysis of stalactites and stalagmites in caves along the "permafrost frontier". This is where ground begins to be permanently frozen in layers that can be tens to hundreds of metres thick. Stalactites and stalagmites only grow when liquid rainwater and snowmelt drip into the caves. So these formations record 500,000 years of changing permafrost conditions - including warmer periods similar to the climate of today.

Thawing of permafrost would have huge implications for ecosystems, says the team

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

West Antarctic Ice Sheet warming twice earlier estimate

The data from Byrd Station shows rapid warming on the west Antarctic ice sheet.

A new analysis of temperature records indicates that the

A report by the UN says global attempts to curb emissions of CO2 are falling well short of what is needed to

stem dangerous climate change. The UN's Environment Programme says greenhouse gases are 14% above where they need to be in 2020 for temperature rises this century to remain below 2C. The authors say this target is still technically achievable. But the opportunity is likely to be lost without swift action by governments, they argue. Negotiators will meet in Doha, Qatar for the UN Climate Change Conference (COP18) next week to resume talks aimed at securing a global deal on climate by 2015.

The Emissions Gap Report 2012 has been compiled by 55 scientists from 20 countries. It says

There have been a few times in the history of mankind when we nearly died out as a species. Anthropologists call these events “bottlenecks”, times when the population of humans shrank – perhaps to as few as 2,000 people over 50,000 years ago. At those levels, we would be categorised as an endangered species on the IUCN Red List, existing in even fewer numbers than wild tigers do today. We survived, and in fact we’ve thrived, mainly because we adapted our environment to suit our needs. But to what degree has the survival and triumph of our species changed our planet? The best people to answer this could well be those who have the grandest perspective. Geologists can take a 4.5-billion-year step back and look at the human impact on our planet in the context of its long history – they can identify changes in the rock record within layers of deposited sediments that build up and are compressed over time. There have been plenty of dramatic changes to our planet in the past: this spinning lump of rock has flipped from a “Snowball” Earth to searing temperatures devoid of ice; there have been times when life has flourished, and times when it has been beset by mass extinctions. Big changes in planetary states show up in the rock record as stripes that reveal the sudden disappearance or appearance of certain fossil species, or climatic changes that reveal changes in past sea level.