In climate, inherent complexity is the enemy of understanding

If complexity is the enemy of understanding, then it's no wonder that folks are confused by climate change.

The climate is so complex that nobody's going to make sense of it in an hour or a day or even much longer.

Take some of the human-caused things that can affect global temperatures, either pushing them hotter or dialing them cooler. This is from the 2009 Climate Change Science Compendium, produced by the United Nations Environment Programme. You can find it here.

Airliner contrails and more cirrus clouds make it warmer.

More sulphates and other reflective aerosols from coal burning make it cooler.

More black soot (can also come from coal burning) makes it warmer.

The tendency of particles from fossil fuel burning to support cloud formation makes it cooler.

Mineral dust blowing up off cleared land makes it warmer.

Reduced ozone in the upper atmosphere makes it cooler.

Increased methane, such as from cows and landfills, makes it warmer.

Making the land surface more reflective, by clearing, makes it cooler.

Increased nitrogen gas from feedlots and biomass burning makes it warmer.

Increased carbon-dioxide, of course, is a big warmer.

And so forth.

Some of these things have a bigger impact on temperature; some smaller. Some last for days in the atmosphere, some centuries.

It's really complex.

On balance, the report says, the result of human activity from the year 1750 to now promotes more warming than cooling.

There are lots of natural, non-human factors that impact climate, of course. One is the sun, whose output can be calculated.

The report estimates the sun is responsible for about a quarter of the amount of climate warming that humans are responsible for in the last 250 years.

The combined total climate forcing of all calculated human impacts during the period in question was about 1.2 watts per square meter. Solar radiation, which has recovered since there was a lower than average intensity in 1750, is calculated at .3 watts per square meter.

It is painfully easy, in the face of the immense complexity, to grasp at one or two facts and draw conclusions from them, rather than taking in the whole picture.

Easy, and commonly done by folks on both sides of the climate discussion, but wrong.

© Jan TenBruggencate 2009