Research by scientists from China, the United States and Europe has revealed that about three billion people out of a total global population of about nine billion could be exposed to temperatures comparable to the hottest regions of the desert by 2070, while indicating that rapid reductions in greenhouse gas emissions can cut this figure in half.
“The good news is that these impacts can be significantly reduced if humanity succeeds in limiting global warming,” said Tim Linton, a research co-author, climate specialist and director of the Global Systems Institute at Britain’s University of Exeter.
The research, which was published by the British newspaper “Financial Times” on Monday, sheds light on how the majority of humans live in a very narrow temperature range of 11°C to 15°C (52°F – 59°F). Despite all the innovations and migrations, people have mostly lived in such climatic conditions for several thousand years.
Global warming has caused temperatures to rise by 1.1 degrees Celsius since pre-industrial times, according to scientists who expect the rise to reach 1.5 degrees Celsius within 20 years, even in the best-case scenario for the desired reductions in greenhouse gas emissions.
At the same time, the research showed that three different climate scenarios and three population projections were developed by the Intergovernmental Panel on Climate Change and the United Nations, in its landmark Climate Change Assessment Report, and in a visualization of the suitability of the Earth in 2070 under these scenarios, The Financial Times paired population projections with each climate model and plotted them across six continents.
The models in question were “developed without accounting for feedback between each other,” said Dr. Jing Zhao, assistant professor of geospatial data science at the University of Delaware.
She added that in the so-called Shared Social and Economic Pathways, we’ve talked about different societal trends, including population, economic development, governance and other relevant aspects – but they don’t really take into account how people react to climate change.
Zhao noted that under the most extreme scenario, by 2070 the southern states of America, especially those bordering the Gulf of Mexico, will become hotter, and Central America will bear the brunt of rising temperatures, where up to 20 million people live in average annual temperatures of 29 degrees Celsius.
The research reported that large parts of Canada and Alaska below the Arctic Circle will see warmer conditions by 2070, and these areas are now largely uninhabited and are expected to remain that way without taking migration into account.
Besides, large areas of the Amazon rainforest in Brazil, along with neighboring countries, such as Peru, Colombia and Venezuela, will be almost unlivable due to the extreme heat projected by 2070, so about 59 million people will be affected by these conditions – or about 12 percent of the projected population of the continent under the most extreme scenario.
The population of Africa is also expected to witness a population explosion in all scenarios of the common social and economic path, with the population doubling from 1.2 billion to approximately 2.4 billion people, and Nigeria is likely to become the third most populous country in the world by the middle of this century, surpassing United States, and Lagos will be on track to become the world’s most populous city in 2075 with 61.5 million people.