Sunday, January 16, 2011

Some recent studies

A summary of a few press releases from ScienceDaily of late.

Putting the dead to work
This study looked at fossils, geochemistry and sediments of the geologic record to see how ecosystems have responded to changes in past climate to try and predict future changes in ecosystems in response. History may repeat after all is the idea. Examples include how warming affected the range of arctic foxes and humans caused the extinction of flightless birds.

Earth's hot past

The earth is hotter than it has been for a long time, and certainly hotter than it would have been without us. The study looks at the climate sensitivity to carbon dioxide and suggests it could be twice what models currently suggest. This is because:

"computer models, which have generally focused on shorter-term warming trends. This is largely because even sophisticated computer models have not yet been able to incorporate critical processes, such as the loss of ice sheets, that take place over centuries or millennia and amplify the initial warming effects of carbon dioxide."

Carbon dioxide does not go away in a hurry in the same way methane does (which in turn ends up as CO2). We need to slow down our rate of emissions or risk reaching 900-1000 parts per million of CO2 by the centuries end, something not seen for 35 million years! Temperatures now would be waarmer than back then for the same green house gas concentrations because of increases in the sun's output.

Land estimates for biofuel crops

Interesting study suggests that 25-26% of liquid fuel consumption could be produced by biofuels on marginal agricultural land.

Species loss and ecosystem collapse/recovery

This study looks at two of the greatest mass extinctions and attributes the ecosystems' collapse to a loss in the variety of species sharing the same space. This serves as a warning given the precipitous decline of key species, such as cod, bluefin tuna, swordfish and sharks, top line predators. The report attributes the ecosystems' collapse to a loss of enough species occupying the same space in the oceans, called "ecological redundancy."

Nice pic of Rockhampton floods

Melt off from small mountain glaciers and ice caps will contribute about 12 centimetres to world sea-level increases by 2100
More detailed study that IPCC projections but roughly consistent examines the role of the smaller glaciers in sea level rise. Melt from smaller mountain glaciers and ice caps is responsible for a disproportionally large portion of sea level increases, even though they contain less than one per cent of all water on Earth bound in glacier ice.

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