Friday, July 26, 2013

Global warming: Charts and graphs

One of the strategies of global-warming deniers has been to control the debate. A few years ago, every conservative talk show would spend part of their time listing places that had record low temperatures, as if they could understand global-warming one bit at a time. Climate scientists have not been so good at framing their own arguments.

For example, in the minority report to the Senate Environment and Public Works Committee, it is stated that there has been a 15-year hiatus in global warming. The report draws the only conclusion it wants people to hear: The threat of global warming is over and we can all breathe easier now. The deniers are not concerned about scientific proof. They are only concerned about influencing voters to protect the big energy producers. Exxon-Mobil earned 15 billion dollars before taxes last year. They can easily afford to spend a couple of hundred million to keep their gravy train moving on down the track.

If you present this finding to a scientist, the first question that comes to mind is, where did all that energy go? We know from scientific measurements that the concentration of CO2 in the atmosphere is increasing at an accelerating rate. This fact is shown graphically in the chart below:

This chart shows the annual increase in CO2 in the atmosphere at Mauna Loa in Hawaii. The black lines show the average increase of CO2 over a five years. The rising black line means that the rate of increase is accelerating to the present year.

These figures show that CO2 concentration was increasing at an accelerating rate. But world temperatures apparently did not increase at an accelerating rate. The amount of energy absorbed by the planet from the sun increased. That energy had to go somewhere. The following chart shows that vast amounts of energy have been absorbed by the earth's oceans:

Chart provided by NOAA
Notice that the temperatures of the land, ice, and atmosphere have not increased greatly in comparison with the temperatures of the ocean. The ocean has been acting as a huge heat sink, absorbing by far the greater portion of increased solar radiation due to increased concentration of CO2 in the atmosphere. The problem for mankind is that the ocean does not retain its heat forever. It is continually releasing its heat into the atmosphere, and the atmosphere has been rapidly increasing in temperature since 1970.

Even if the temperatures were receding, as proclaimed by the deniers, the energy is still building up in the oceans. This energy will affect the climate of the planet for hundreds of years and more. The daunting task ahead of us is to reverse the absorption of energy by reducing the amount of CO2 and other greenhouse gases we release into the atmosphere. Other effects of global warming so dear to the deniers, such as melting ice-caps, more violent storms, and flooding, are only by-products of the vast amounts of energy we are storing up on our planet.

The deniers don't want to discuss abstractions like energy, which are difficult to deny. They prefer to discuss CO2, which is invisible, and temperatures at particular locations, which everyone understands. Scientists have a different perspective on the planet, however. They have been having difficulty convincing the rest of us about the dangers we face from global warming.

The scientists have been having no difficulty whatever convincing each other. So few papers have been written by deniers that it's hard to display them graphically. The last chart is an attempt to do just that:

Chart provided by James Russell Powell and DeSmogBlog

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