Extreme Summer Heat Likely to Persist for Six Months a Year in Tropics by 2100, According to a New Research Report

According to a new study published in the journal Communications Earth & Environment, anthropogenic CO2 emissions will significantly increase global exposure to dangerous heat environments in the coming decades. The research, conducted by a team of researchers from Harvard and the University of Washington, suggests that even if the world meets the Paris Agreement of limiting global warming to 2°C, the risk of dangerous heat occurring across tropical regions will increase by 50-100%.

The study does not provide specific temperature increases for each region, but it does indicate that in tropical regions, up to half of the days in a year could have "dangerously hot" weather, reaching or surpassing 39.4°C. In some regions, such as Northern Australia, extremely hot weather could become the norm, with the "extremely dangerous" heat index threshold - when temperatures reach 51°C - likely being exceeded on more than 15 days each year.

Regions most likely to experience the highest temperatures by the end of the decade include parts of the tropics and mid-latitudes. The greatest warming is projected in areas such as the Middle East, North Africa, and parts of South Asia due to climate change-driven heat extremes. In many regions throughout the midlatitudes, the risk of extreme heat will increase by a factor of 3-10.

Extreme heat will occur three to 10 times as often in western Europe, the US, China, and Japan by the end of the decade, according to the study. The global Heat Index, a metric combining air temperature and humidity to quantify the actual heat exposure in human beings, is expected to change significantly due to these emissions.

Lucas Vargas Zeppetello, one of the lead authors of the study, stated that the difference between limiting carbon emissions to meet the Paris Agreement and not doing so is "hugely consequential for billions of people, primarily throughout the global south." The health consequences of regular very high temperatures, particularly for the elderly, poor, and outdoor workers, would be profound and require a basic reorientation to the risks of extreme heat.

The team of researchers combined historic climate data with future projections of population and economic growth as well as carbon emission scenarios to estimate global temperatures in the future. The study does not specify the exact definition of a "dangerous heat environment" in the context of the research.

In summary, the study highlights the urgent need for action to reduce CO2 emissions and limit global warming to prevent an increase in dangerous heat environments across the globe. The consequences of inaction, particularly for vulnerable populations, could be severe and far-reaching.