I remember the widespread public anxiety and depression in the 1960s and 1970s at the prospect of mutually-assured destruction and nuclear winter in the event of a global nuclear war. And today, public anxiety ("eco-anxiety") over climate change is growing worldwide. The American Psychiatric Association recognises climate change as a significant threat to mental health. Eco-anxiety is a normal reaction to public warnings about the consequences of climate change, but it is unhealthy when it becomes excessive.
There is very good reason for concern about global warming. The latest report (August 2021) from the UN intergovernmental panel on climate change (IPCC) shows that Planet Earth is in poor shape. Atmospheric greenhouse gas concentrations are higher than ever before in recorded human history, average global temperature is 1.2 degrees warmer than preindustrial temperature and rising, oceans grow more acidic, ice sheets are disintegrating, natural disasters are worsening and ecosystems threaten to collapse. Emissions of greenhouse gases from human activities have caused all this.
But matters are far from hopeless, as nicely summarised by Sarah Kaplan in the Washington Post. The IPCC reports that if we drastically reduce greenhouse gas emissions, reaching net-zero emissions in the next few decades, difficult to achieve but doable, we stand a good chance of limiting global warming to 1.5 degrees above preindustrial levels. A 1.5 degrees rise would trigger extra adverse conditions – longer heatwaves, more intense rainfall, more frequent droughts, but within our capacity to cope.
On the other hand, if we don’t further reduce emissions, average global temperature will likely soar 2 degrees above preindustrial levels by 2050, and by the time today’s babies draw the old-age pension, warming could approach 4 degrees. This would be very serious – for example, major storms would carry much more rain, droughts would occur five times more often, multiple natural disasters could combine (“compound events”) causing widespread chaos and intense warming might trigger runaway weather changes.
One frightening possibility is shutdown of the Atlantic Meridional Overturning Circulation (AMOC), the currents that transport heat through the oceans. If AMOC halted, intense cold could grip Europe and parts of North America, sea levels would rise significantly and seasonal monsoons, providing water to much of the world, would be disrupted.
These projections are attended by large uncertainties; for instance, we don’t know how much warming would stop the AMOC. However, we are already experiencing trouble from current warming and we know for sure that further global warming will cause more trouble. We would be crazy to test the accuracy of climate modelling predictions by not drastically cutting emissions as soon as possible.
There is no shortage of commentators claiming human-induced climate change has already doomed the planet or will shortly do so if we don’t achieve certain unattainable targets within several years. These predictions induce widespread depression, even despair. Many young people feel reluctant to have children, fearing they will inherit a ruined earth.
The situation is analogous to growing old, encountering inevitable gradual deterioration of the body
But science doesn't support despair. Climate change will not destroy human society. There is no foreseeable temperature at which all will be lost. We will survive even under very difficult circumstances but the more effective the actions we take now, the better our prospects. Every tonne of carbon dioxide we emit to the atmosphere increases warming, every tonne we forego emitting lessens the warming impact. Say we don't succeed in limiting temperature rise to 1.5 degrees and it rises by 1.7 degrees. Well, that's better than 1.8 degrees and 1.8 degrees is better than 2 degrees.
The situation is analogous to growing old, encountering inevitable gradual deterioration of the body. You can get depressed and do nothing or you can make the best of things, follow medical advice about diet and exercise and greet every day knowing your situation is probably as good as it gets. We can improve the climate situation through personal action (driving electric cars, using public transport, insulating houses, minimising waste, etc) and by lobbying Government to act.
Finally, we must hope that scientific breakthroughs will ameliorate the situation relatively soon, for example by facilitating largescale removal of greenhouse gases from the atmosphere. While two climate modellers won the 2021 Nobel Prize for Physics, the Nobel committee should establish a climate change prize to be awarded to scientists who achieve revolutionary breakthroughs; a proposal that should be canvassed at COP26, the UN climate summit in November.
William Reville is an emeritus professor of biochemistry at UCC