How to avoid a billion climate deaths

The number of human deaths caused by climate warming over the next century must be one of the more critical pieces of data needed to plan for the future survival of the human population.

Over several decades, scientists have developed valuable knowledge and expertise on the impacts of climate warming on animals and birds as well as landscapes and oceans. They have shown that 75 percent of New Zealand indigenous fauna species are facing extinction. It is logical then that they are turning their attention to the mortality of humans caused by climate warming over the coming century.

Some of the approaches for the prediction of climate-caused human fatalities are underpinned by the empirical relationship that one climate-caused death occurs for every thousand tonnes of carbon dioxide emitted. This 1000-tonne rule, recently confirmed by a survey of 180 peer-reviewed research papers, has led researchers to the conclusion that unless we have significant carbon emission reduction, one billion climate-caused human deaths are projected to occur over the next 100 years.

This challenging conclusion has been reported by Professor Joshua Pearce from Western University in Canada in The Conversation and by Professor Richard Parncutt from the University of Graz in Austria in the journal Frontiers in Psychology.

This semi-quantitative finding has attracted wide attention from the United Nations, World Health Organization and dozens of international scientific organisations and economic publications.

The authors note that this number of climate deaths may be larger or smaller but is expected to be accurate within one order of magnitude. Put in another way, it is expected to be between 300 million and 3000 million deaths within a century – a median figure of 1000 million or one billion deaths has been adopted for simplicity.

Any deviation from the median 1000 million deaths over the next 100 years will be followed and calculated by scientists with greater precision following every regular update as humanity proceeds along this current lethal path. The only way for the planet, including New Zealand, to avoid catastrophe is to urgently reduce carbon emissions by shifting away from fossil fuels to renewables.

Given the very large demographic population numbers involved, let me put the one billion deaths in clearer perspective. Using well-established demographic figures, the proportion of climate deaths (1000 million or one billion) to total planetary population (11000 million or 11 billion) would then be, in 2100, approximately 9 percent of the global population.

Why are so many humans predicted to die because of climate change? The number of fatalities caused by extreme temperatures will inevitably be greatest in the highly populated hot equatorial zone of the planet. This zone also includes some of the highest regions of poverty.

However, exceptional temperatures are only one of several climate change impacts. Drought is another; it destroys traditional food sources which forces local populations to move across the landscape in search of new ones. If that search is not successful, it can lead to starvation, famine and conflict.

According to the European Parliament Institute of Economics and Peace, there could be 1.2 billion climate refugees by 2050. Poverty is obviously a key factor in this trend. As the World Economic Forum and the World Bank report, only one tenth of the world’s greenhouse gases are emitted by 74 low-income countries, and yet these poorer countries will be selectively devastated by the effects of climate change including exceptional temperatures.

The projection of a billion deaths over the next century is currently of great concern to younger generations who must contemplate both the impacts on their life ahead and even on their survival chances. To balance this, the same generations will have a unique opportunity to be involved in the rapid growth of the renewable revolution (see below) and so become an essential part of the solution to climate change.

The only practical solution to the looming threat of climate fatalities will be the adoption of an ambitious renewables strategy to achieve zero-carbon emissions. These technologies already exist and in all cases are being scaled up to serve national energy targets. At this early stage, the most advanced renewables on the international stage appear to be large-scale solar and wind, plus electric vehicles.

Many other renewables are already being developed rapidly in some countries and all of these together will play a global role in reducing emissions. One example, tidal energy, is being developed in Japan with submerged turbines to supply 60 percent of the national demand. Other regions have unique natural advantages such as North Africa, including Algeria, which has the highest solar and wind potential on the planet, meaning they are expected to play a key role in green energy partnerships with European economies.

The green hydrogen renewables era is being ushered in by China, which also leads the world in electric vehicle production. The US is rapidly developing hydrogen electrolysers and recently developed zero-carbon concrete. Airbus and Rolls Royce are leading the development of hydrogen-powered airliners. Sweden has developed a zero-carbon steel production plant using hydrogen in place of coal. There are many more.

There are logical reasons to be optimistic about the future but only if we can attain zero-carbon status through adopting practical renewables and avoid the risk of many hundreds of millions of climate deaths.