CO2 greenhouse gas

Your correspondent John Caldwell (Times, July 13) claims: “CO2 is vital in regulating the Earth’s temperature”.

He also claims: “The percentage of CO2 in the atmosphere has been constant at 0.028 per cent for 4 million years” [prior to 1800].

If CO2 controls the planet’s temperature, and has been constant for 4 million years, how is it that the Earth has been through multiple ice ages and inter-glacial periods in that time?

Through periods where most of North America was under hundreds of metres of ice and through periods where you could grow grapes in Northern England and farm in Greenland?

Through periods where sea level changes have made it possible to walk on land from what is now London to what is now Amsterdam? And have turned seas into deserts?

All these dramatic changes were happening long before man figured out that he could burn stuff that he dug out of the ground.

And how is it that even though human consumption of ‘fossil’ fuels has fluctuated dramatically over the last 150 years, that CO2 concentration has risen at a more-or-less constant rate in that time?

And how is it that even though the increase in CO2 concentration has risen at a more-or-less constant rate, temperatures have fluctuated from the dust-bowl highs of the early 20th Century to “the ice age is coming” lows of the 70s and now back to the levels of a hundred years prior in the early 21st Century?

Either he is wrong that CO2 was constant, or he is wrong that CO2 is the ‘vital’ controller of the Earth’s temperature.

I would argue that the evidence suggests he is wrong about both.

While CO2 may be a factor in the Earth’s climate equation, it seems to me that the geological and meteorological records contradict the claim that it is ‘the vital factor’.

The Earth’s climate changes on cycles that we’re only just beginning to recognise, never mind understand.

The only constant of climate is that it changes. It is absurd to try and control it and a conceit to think that we can.

Even climate scientists do not dispute that we are currently between ice ages – in a rare (geologically speaking) inter-glacial period where the temperatures are warm enough to support a flourishing of civilisation.

If we’re lucky, we’re still near the beginning of it. If we’re unlucky, then the “ice age is coming” predictions of the 1970s may come to pass sooner than we’d like. And an ice age will be much worse for us than even the worst-case warming scenarios.

The trillions of dollars being spent on trying to prove that humans are causing climate change by burning fossil fuel and in efforts to undo the alleged damage, would be much better spent learning how to adapt to an ever-changing climate.

On how to build infrastructure to protect humans, plants and animals from the inevitable future changes.

And on helping to raise the millions of still impoverished people around the world into something resembling prosperity, so that they too can prepare their environments for the ever-changing future their children will inherit.

Ryan Price
Half Moon Bay