Saturday, June 27, 2009

Northerly winds and global warming

This morning we awoke to a welcome change – northerly winds. The air temperature was noticeably milder.

It also meant that we had to swing into action with the CO2 sampling programme, which has to be conducted with a not-too-strong and not-too-light breeze moving in off the sea. Raoul Island is part of a world-wide network of sampling sites that contribute data to the Scripps Institution of Oceanography in the USA.

This is part of a continuing scheme of work begun by Dr Charles Keeling in 1955. He was the first scientist to recognise that the amount of carbon dioxide did not vary from place to place (apart from seasonal variations as trees drop their leaves and return to the atmosphere the CO2 they have absorbed over the growing season).

His insistence on continuing to measure the air samples at remote and unpolluted places has allowed him to construct the Keeling Curve – a graph that tracks the levels of carbon dioxide in our atmosphere; over the years, it climbs almost as steeply as do the walls of our volcano.

His discovery alerted other scientists to the potential dangers of global warming. They surmised that a build-up of carbon dioxide in our air would act as an insulator – the so-called greenhouse effect. One predicted result of this build-up is the wild swings in weather that the world seems to experience more and more frequently.

Ready to hold breath!

Bas and I had to carry two sealed glass flasks down to the beach, stand 10 feet apart, face the wind, hold our breath and open the nozzle to collect the air samples. Apparently the measurement of these samples is so precise that it can be determined whether the air has passed over vegetation or the person holding the flask drank alcohol during the previous evening. This is why we had to hold our breath.

Bas packing off the samples ready to go to the USA

Now we have done our little bit for science, we are able to relax and enjoy the weekend.

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