Scientists reveal what happens when Earth gets two degrees warmer

In a recent study led by Nasa, scientists have warned that if global temperatures continue to rise and reach 2 degrees Celsius above pre-industrial levels, people worldwide could face multiple impacts of climate change simultaneously.

The research indicates that over a quarter of the world's population could experience an additional month of severe heat stress each year compared to the mid-20th century.

The study also predicts that high temperatures and drought could dangerously combine in places like the Amazon, increasing the risk of wildfires. In the American West, extreme fire weather is likely to be more intense and last longer.

To conduct this research, scientists used a set of climate predictions generated by 35 of the world's leading climate models, including those developed by the Nasa Goddard Institute for Space Studies.

These models are part of the Coupled Model Intercomparison Project (CMIP), which provides climate projections to help international and national climate groups understand historical, current, and future climate changes.

“We wanted to study how these aspects of the environment are projected to change and what their combined impacts could mean for people around the world,” said Taejin Park, the first author of the paper.

They looked especially at heat stress – or the combined effects of temperature and humidity on the human body – and fire weather – which considers temperature, rainfall, humidity, and wind.

The researchers at the Nasa Earth Exchange (NEX) then used advanced statistical techniques to "downscale" these predictions, significantly improving their resolution. NEX uses supercomputers at Nasa’s Ames Research Center in California's Silicon Valley to analyze vast amounts of data collected by aircraft and satellites or, in this case, projections produced by climate models.

The team analyzed the downscaled projections to assess the changes predicted for six key climate variables, including air temperature, precipitation, relative humidity, short- and long-wave solar radiation, and wind speed. They found that most regions of the world will experience higher heat stress, while countries closer to the equator will suffer from a greater number of days considered extreme.

"The escalating impacts of all the climate extremes studied could cause significant damage to communities and economies, from fires, floods, landslides, and crop failures that may result," said Ramakrishna Nemani, senior scientist at the Bay Area Environmental Research Institute (BAERI) and co-author of the study.

The findings hint at the urgent need for global action to mitigate the dangerous effects of climate change.