Global Warming (1970–Present)

Abstract

From 1970 to 2017 global temperatures (land and ocean) increased by ~0.9 °C. Models indicate that most of the global surface temperature increase can be attributed to greenhouse gases. The Arctic has warmed particularly rapidly owing to feedback processes such as ice-albedo feedback and feedbacks involving clouds and water vapor. Atmospheric warming since 1970 has a clear vertical structure. In the Arctic, warming has been strongest near the ground, where feedback processes operate most strongly. In the tropics, by contrast, the warming has been greatest at an altitude of ~10 km. Since the 1950s, there have been more heatwaves and fewer cold nights. Trends in precipitation are much less clear than those in temperature, but there are indications that heavy precipitation events have intensified. The frequency of tropical cyclones has not changed, although there is evidence for an intensification of Atlantic hurricanes. The period since 1970 has brought many noteworthy climatic events, including droughts in the Sahel in the 1970s and 1980s, a change in European winters around 1990, effects of volcanic eruptions, and large El Niño events, as well as droughts in the new millennium.