Global temperatures are likely to reach record levels in the next five years, according to an annual update released May 17 by the United Nation's World Meteorological Organization.
WMO scientists predict a 66% chance that the annual increase in mean global surface temperature will temporarily exceed 1.5 degrees Celsius above pre-industrial levels for at least one year between now and 2027.
While 2016 was the warmest year on record so far, the chance of at least one year between 2023 and 2027 exceeding that is 98%, with equal odds that the five-year period will be higher than the last five years.
Greenhouse gases and a naturally occurring El Niño event are the main factors, the WMO update said.
Along with increased global temperatures, human-induced greenhouse gases "are leading to more ocean heating and acidification, sea ice and glacier melt, sea level rise and more extreme weather," WMO said.
WMO Secretary-General Petteri Taalas said in a statement that the report does not mean that temperatures will permanently exceed the 1.5°C level specified in the Paris Agreement, but "we will breach the 1.5°C level on a temporary basis with increasing frequency."
Before 2015, there was little chance of temporarily exceeding 1.5 degrees Celsius, and between 2017 and 2021, there was a 10% chance. Now, "global mean temperatures are predicted to continue increasing, moving us away further and further away from the climate we are used to," said Leon Hermanson, the scientist leading the update, in the statement.
