The Pacific Ocean is not only the largest continuous body of water on this planet but it has the largest continuous bodies of water in the skies above it – the clouds in the sky. Some of them as bigger than some of our continents and clouds are one of the many things that keep the climate of our planet stable enough to support human life.
They reflect radiation back into space and absorb radiation from the sun, preventing the oceans from becoming too warm. Although we know how they do this, when scientists come to model the climate which is changing, in order to predict the likely changes they do not accurately understand the precise role that clouds play, and that makes modelling and prediction very difficult.
In the next month scientists from ten countries will try to model these massive Pacific Ocean clouds and put the data they get into their existing climate change models. We may then get better prediction of climate change and a better understanding of how urgent the measures we must take really are.
So far the planet talks a good game on climate change but does not really do much more than that. Climate change modelling is a matter of genuine scientific complexity and although knowing more about clouds is helpful, very helpful, it will still leave this massive three dimensional jigsaw incomplete.
The extent of the complexity can be illustrated by looking at three research projects that are contained within the study that is being undertaken. The marine stratocumulus clouds which are present almost all year round in the Pacific and can extend to 2 kilometres in thickness will be visited by aircraft with dust probes, in order to understand better how they are formed and how long they last.
Pollution in the South Pacific clouds will be measured. There is plenty of mining carried out on the Western coast of South America, particularly copper mining in Chile, which creates particulate dust that is carried in the air and in the clouds, forming water droplets around them. We need to know how they work. We also particularly need to know that the activities that we humans are doing will not be making the clouds last for shorter periods; if this is happening climate change will accelerate.
Clouds have an albedo – the ratio of the intensity of the outgoing radiation to the incident radiation.
An example of the effect is when snow melts. The albedo decreases and therefore, it melts faster. It collects solar energy much more quickly as it melts - because it as it melts it can reflect back less solar energy.
With clouds different clouds have different albedos. Some can reflect back virtually no energy and others can reflect back 70% of the solar energy that strikes them. Usually the earth is half covered with clouds keeping the earth cool by reflecting back energy while also preventing the energy below them from bouncing back into space.
I am both amazed and in awe of the complexity and the fragility of our climate - a slender sliver of particular warmth that enables us to inhabit the planet without boiling or freezing and that enables life to prosper. The temperature range is tiny compared with possible temperatures from absolute zero to millions of degrees.
For hundreds of thousands of years the planet has kept its energy balance within this range, all by the movement and vibrations of molecules. If they stop moving we have absolute zero; if they move too fast we vaporise and clouds are just one of the many devices that keep the molecules moving at just the right rate – not too fast and not too slow.
Joni Mitchell wrote and sang
I’ve looked at clouds from both sides now
From up and down, and still somehow
Its cloud illusions I recall
I really don’t know clouds at all
And she was right – we really do not know clouds at all.
Filed under: carbon emissions, climate change, energy, global warming, pollution | Tagged: absolute zero, albedo, albedo effect, clouds, joni mitchell, Mining in Chile, vibration of molecules
interesting blog. i suppose i should appreciate clouds more