At the time of the industrial revolution and for thousands of years before the average amount of CO₂ in the atmosphere has been estimated as about 280 parts per million or ppm (in other words, out of every million molecules in the air 280 were CO₂, not much: 0.00028%). In 1958 when this was first measured (as opposed to estimated from other data) it was 315. In 2000 it was 367. Today it is near 380 – and rising. A word of caution is in order here. CO₂ is not the only greenhouse gas in the atmosphere. There are others, especially methane (which is a product of agriculture). Total greenhouse gas presence in the atmosphere is measured in terms of CO₂ equivalent. Today this is about 430 ppm. And this is the figure that is generally referred to in discussions on the subject. It’s as well to be aware that when this figure is quoted not all of it is made up of CO₂, but is a figure for all greenhouse gases. CO₂ equivalent is about 15 percent higher than the figure for CO₂ alone.

Socialists are not scientists so all we can do is to exercise critical thinking while taking into account what the majority of scientists in the field have concluded, knowing that they could be wrong.

The majority of scientists in the fields involved have concluded that the undeniable rise in average global temperatures has been caused since at least the 1970s by the rise in the amount of CO₂ in the atmosphere due to the burning of fossil fuels. In other words, that it is man-made or “anthropogenic” as they put it in their language.

What is not clear – scientists are still arguing about it – is what precise temperature rise is caused by the emission of a given extra amount of CO₂. This of course is a key ratio since more and more CO₂ is being released into the atmosphere by the continued burning of coal, oil and gas.

If you assume the “climate sensibility” of CO₂ to be low, then the rise in average global temperature at particular levels will be low. If you consider its “climate sensibility” to be high, then by 2100 the rise could be 2, 3 or 4ºC. A 3 or 4º rise could cause huge problems: sea levels rising by a third to a half a metre (one or two feet), more stormy weather, more forest fires, more droughts and desertification.

So, without necessarily subscribing to the higher figures put forward by the more engaged scientists, it can be accepted that it is desirable to cut back on CO₂ emissions. The question we look at in this issue is how likely is this to happen under capitalism given its competitive and anarchic nature?

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