A new study shows the Earth’s climate would increase by 4 degrees Celsius, compared to pre-industrial levels, before the end of 21st century. The study also projects precipitation changes in association with a 4 degrees Celsius global warming above the pre-industrial period using the available RCP8.5 experiments of CMIP5 models.
“A great many record-breaking heat events, heavy floods, and extreme droughts would occur if global warming crosses the 4 °C level, with respect to the preindustrial period,” said Dabang Jiang, a senior researcher at the Institute of Atmospheric Physics of the Chinese Academy of Sciences. “The temperature increase would cause severe threats to ecosystems, human systems, and associated societies and economies.”
In the analysis, Jiang and his team used the parameters of scenario in which there was no mitigation of rising greenhouse gas emissions. They compared 39 coordinated climate model experiments from the fifth phase of the Coupled Model Intercomparison Project (https://www.wcrp-climate.org/wgcm-cmip), which develops and reviews climate models to ensure the most accurate climate simulations possible.
They found that most of the models projected an increase of 4°C as early as 2064 and as late as 2095 in the 21st century, with 2084 appearing as the median year.