DERMOT WILLIAMSON: Net Zero... what and why
Net zero is much in the news. But what is it?
Does it matter for us in Badenoch and Strathspey, in Scotland, the UK and the world?
This is the first of a series of articles that will try to answer these questions.
This article explains what net zero is and why it is important.
July, August and September were the hottest recorded for those months. This last 100 years has been the warmest for the world in the past 100,000 years.
Global warming is now about 1.2°C. That means the world is on average1.2 degrees centigrade warmer than before 1850 – 1900, that is before the Industrial Revolution.
The International Energy Agency in October estimated that current progress is heading the world towards global warming of 2.4°C.
The IPCC, a United Nations body of scientists from 195 countries, warns that even 2°C of global warming would bring worse wildfires and floods than now, risks to water, food supply, health of hundreds of millions of people, livelihoods, and economic growth, and extinction of species.
Each tenth of a degree of warming significantly increases storms, floods, wildfires and other dangers of climate change.
What we are suffering now is just a bitter foretaste of what may come if global warming continues to 2.4°C.
Why is this happening? Greenhouse gases (GHGs), such as carbon dioxide (CO2), in the atmosphere trap heat from the sun, insulating the world as if we were in a greenhouse.
We have emitted CO2 by burning fossil fuels, such as coal, oil and gas.
Nature also emits and captures GHGs from plants, animals, land and oceans. But before the Industrial Revolution natural emissions and natural capture kept the amount of GHGs in the atmosphere fairly constant.
That is why average temperatures were fairly constant compared to today.
The established scientific consensus is clear (IPCC, 2023, Synthesis Report), to halt global warming, we must stop increasing GHGs in the atmosphere.
Then emissions of GHGs would be ‘net zero’, because GHGs emitted would equal or be less than those captured from the atmosphere.
At net zero, GHGs in the atmosphere would again be at a fairly constant level, although higher than before the Industrial Revolution. The world would be warmer than in 1850 but not continue getter ever warmer.
Net zero is part of many plans to halt global warming and many international agreements.
Much discussion at the United Nations’ COP28 climate conference from November will be about how and when to achieve net zero.
These discussions and plans will greatly affect whether the world will continue only a little warmer than today, or become unbearable for our children and descendants.
• Dr Dermot Williamson is a retired chartered accountant and academic, who now lives in Kincraig. He has followed the physical and social sciences of global warming for several years.
