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Climate science was ahead by a century

Over the years, I have often expressed my perplexity at the various people and organizations which form the "anti-global warming" crowd. I have struggled to understand their motives.
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Over the years, I have often expressed my perplexity at the various people and organizations which form the "anti-global warming" crowd. I have struggled to understand their motives.

It's easy to dismiss people saying they don't understand science but it would be incorrect, as many of the AGW activists are scientists of one form or another. Some are just armchair amateurs but even they tend to spend their time reading about the subject.

My perplexity arises, in part, because the science on the subject is so clear and has been for a very long time. Sure, there are details to fill in, but details are details and it is highly unlikely they will have the weight to completely overthrow our understanding of atmospheric science.

The idea the atmosphere blankets the planet and keeps us warm dates back to 1824. The mathematician Joseph Fourier was interested in a very simple question: what determines the average temperature of a planet like Earth?

His calculations led to the recognition that while the sun is the ultimate source of heat, the gases in the atmosphere absorb radiation and warm the Earth. Without the atmospheric greenhouse gases, the Earth would be a very much colder place - with an average temperature of around -18 C.

In effect, Fourier was using mathematics to model the atmosphere and to make predictions about the way atmospheric gases and heat interact. While mathematics is good, better is to have experimental evidence. This was provided in 1858 by the British physicist John Tyndall who demonstrated the absorptive heat capacity of atmospheric gases.

Further evidence came in 1896, when the Swedish chemist Svante Arrhenius quantified the effect. He went on to predict the wholesale combustion of fossil fuels by industry would ultimately change the atmosphere.

Yes, the science would appear to have been settled over 100 years ago.

But even in Arrhenius' day, many scientists didn't believe human beings could have a global effect. Instead, they clung to the theory any excess carbon dioxide generated by human activity would be readily absorbed by the oceans of the Earth.

They weren't entirely wrong. The oceans are a good sink for carbon dioxide. However, they haven't been able to keep up with our rate of production.

An analogy might be going to a sporting event. As long as spectators arrive at a slow and steady pace, there isn't a line up at the door. But when a large number arrive over a short period of time, a crowd forms and people have to wait to get in.

In the case of carbon dioxide, our excess production will eventually end up dissolved in the ocean, but not any time soon. The rate of absorption is too slow. Instead, it will hang around in the atmosphere waiting to dissolve. In the meantime, we just keep adding to the crowd.

In 1938, G.S. Callendar estimated that between 1890 and 1938, around 150 million tons of carbon dioxide was pumped into the atmosphere from the combustion of fossil fuels and 75 per cent remained in the atmosphere. The oceans were not acting as a sink fast enough.

The steady rise in carbon dioxide levels over the past century are beyond dispute. The science stands on solid ground. The time series of carbon dioxide measurements at Mauna Loa since the 1950s provides graphic evidence of this increase.

By 1981, James E. Hansen and co-workers at the Goddard Institute for Space Studies were able to show, with the inclusion of a proper model of ocean mixing, the average surface temperature of the Earth could be accurately modelled by taking into account all of the forcing trends - carbon dioxide levels, volcanoes and solar output.

This work pretty much laid to rest any notion changes in the mean surface temperature during the last century were solely due to variability in solar output or a consequence of aerosols from volcanoes. All three components are necessary, but it is the increasing levels of carbon dioxide which lead to a warmer troposphere.

This is one of the arguments demonstrating anthropogenic heating of the atmosphere. The troposphere is getting warmer faster than the stratosphere. The atmosphere is getting hotter from the bottom up, consistent with anthropogenic warming and not from the top down as predicted for solar variation.

In any case, the science of climate change has been known, verified, peer-reviewed, analyzed, checked, cross-examined and has stood the test of time. So, why are there still people that insist it is not happening?

Yet here we sit with the largest per capita emitter on the planet run by a man who would deny the existence of climate change. He believes in laissez-faire economics and does not recognize external costs.

The science of climate change has been trumped by political ideology and until that changes we are all going to pay the price.