Weather Forecast


We just don't know clouds

A new United Nations report suggests an imminent danger from global warming. It states that without drastic action we may have “to develop the ability to suck greenhouse gases out of the atmosphere and store them underground”.

Minnesota already has millions of devices which do that. They are called trees and plants. They take in carbon dioxide (CO2), store the carbon (C), and return the oxygen (O) for us to breathe.

It is actually not clear that our fossil fuel burning CO2 emissions are a serious global warming threat. There are many poorly understood ocean temperature variables which have a bigger impact on earth temperatures. These include the El Nino cycle and the Pacific Decade Oscillation. Confusion over how those work helps to cause the UN’s Intergovernmental Panel on Climate Change (IPCC) to regularly over estimate temperature warming trends.

Undeterred, federal and state legislatures are spending billions in response to guesses about our climate future. In addition to ocean cycles, there are several other poorly understood natural climate feedbacks. These act as natural thermostats, keeping the earth’s average temperature during inter glacial periods within a fairly narrow range. One of the most important is the action of clouds. Clouds are water vapor, a green house gas which warms us. Clouds reflect the sun’s light, cooling us. Clouds produce rain which removes CO2 from the atmosphere, etc.

A few lines from a popular song about clouds, “Both Sides Now”, pretty much sums up where we are with clouds and other climate variables:

“But now they only block the sun, they rain and snow on everyone.

So many things I would have done but clouds got in my way.

I’ve looked at clouds from both sides now, from up and down, and still somehow ...

It’s cloud illusions I recall. I really don’t know clouds at all.”

At this point, no one knows how to accurately plug the impact of clouds or other climate variables into climate forecasting models.

ROLF WESTGARD is guest faculty on energy subjects for the University of Minnesota Lifelong Learning. He recently taught “America’s Climate and Energy Future: the Next 25 Years.”