ICE CORE DATA OF GLOBAL MINED TO EXPLAIN TIME LAGS BETWEEN CO2 RISE AND TEMPERATURE SPIKES.

Finding clues to climate change at time means exploring places most people can't see or think of.  

One of these is the thick ice layers in the poles.  

Scientists have long experimented by cutting as much as one mile of ice to get to different stages of deposit of the ice that make the ice layers.  The longer the ice core section, the more time can be 'read' from it.

One of the answers scientists are seeking is that regarding a spike in global temperature and why there seemed to be a lag of 1400 years between CO2 levels increase and the spike in global temperatures.  

The study of ice cores however, can go back to almost one million years ago.   The deposits of CO2, and air temperatures at different stages is a very good metre with which to measure changes that have occurred in the atmosphere through time.  

One of the question that has baffled scientists so far, is whether the CO2 spike is caused by a rise in temperatures of viceversa, since there seemed to be such a wide span of time in between the two.  

In one study for example, done by mining ice cores in Antarctica, the CO2 levels seemed to lag behind the rise in temperature.  The lag appeared to have been as long as 1,400 years.  This had given rise to a very vocal opposition to the supposed influence of rising global temperature on the levels of CO2.

But new findings by a team of scientists with the Laboratory of Glaciology and Geophysical Environment might have finally found the answer to the riddle.  The new observation of 5 ice cores collected in the past 20 years now show that that lag to be much shorter, as short as 200 years between rising temperatures and soaring CO2 levels.

The secret, scientists say, to this much clearer finding, has much to do with the way ice is collected and compacted with time on the polar surfaces.  The air containing the CO2 gases are trapped in the compacting ice, but are much lighter thereby becoming mobile through the ice pack and diffusing throughout.  In this way the air bubbles could be younger than the ice deposited, so that if there is less snowfall in one locale, the age difference between the gas and the surrounding ice can be thousands of years whereas in others it could be as short as 200 years.



The new data could help in convincing some on the need to act on global warming.

partial source: Scientific American 3.2.13