Time for rich nations to face hard climate truths at Cop27
George Monbiot is correct – the geological record shows a series of disastrous extinctions caused by the climate system being pushed beyond tipping points (Fossil fuel burning once caused a mass extinction – now we’re risking another, 3 November). Although such tipping points might soon be reached, it’s more persuasive to know exactly where the system is right now.
You report that temperatures in Europe are now rising by around 0.5C per decade, equivalent to 5C per century (Europe’s climate warming at twice rate of global average, says report, 2 November). Compare this rate with the end of the last ice age, when the system was entering its present relatively warm state. Evidence from fossil insects in Britain shows that by a conservative estimate, the average temperature rose by 1.7C to 2.6C per century, with maximum possible rates inferred from the same data up to 2.8C to 7.2C per century.
The climate system then was adjusting to natural increases in greenhouse gases, but today they are manmade. There seems no room for doubt that we have already pushed the system to the very edge of the envelope of natural rates of change, and possibly beyond it. This is in Britain, not some faraway, low-lying country beset by sea level rise.
The global system is still responding to the emissions that we have already made, and if we do not stop right now, it may continue until it reaches the same equilibrium state that it had the last time that carbon dioxide levels were as high as today. That was 3 million years ago, and sea levels were over 20 metres higher. Never has serious and effective action been more urgent to reduce absolute levels of greenhouse gases, not just emissions. Tim Atkinson Emeritus professor of environmental geoscience, University College London
• Isabel Losada’s climate crisis optimism is dangerously misguided (Cop27 is here and the climate crisis is daunting but here’s the key to tackling it – cheer up, 4 November). Her article appeared at the same time that the Guardian reported the UN chief predicting “we will be doomed”; “the best year ever” for oil and gas companies; 20 million people in Pakistan needing humanitarian aid; floods and droughts worldwide; graphs of rising carbon dioxide emissions; tropical primary forest loss; rising methane emissions; sea level rise; loss of Arctic sea ice; Donald Trump “very probably” running again; and so on.
Yes, we still need to do all the things that Ms Losada suggests, and much more, but it is way past the time when we can afford not to be seriously scared about the future. Some realism is needed when surveying the damage already under way with just one degree of warming, and the relative inaction of the political realm worldwide.David CotteeFulbourn, Cambridgeshire
• On the day that the Grenfell inquiry ended, we had the coincidence of Cop27 beginning, in which the prospect of the very same criminal sacrificing of lives to save money is at work on a global scale.
Our rich nation leaders, many quick to condemn the outrageous cost-cutting that caused the Grenfell fire, cannot plead, with any sense, a lack of funding to ensure that the people of developing nations are not also incinerated in face of the global warming that the rich have caused. It is more than possible to break out of that doom loop by investing in a sustainable way of living for all. We have no choice but to fight that war for sanity. Adam HartLondon •
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