El Niño is a naturally and irregularly occurring warming of surface ocean waters in the eastern tropical Pacific whilst solar variation is the change in the amount of radiation emitted by the sun, dominated by an approximately 11-year-long cycle. Volcanic eruptions predominantly have a cooling effect lasting a few years, due to the very tiny erupted particles and droplets shielding light from hitting the Earth. The three surface temperature data sets scrutinized by the researchers were from NASA, the National Oceanic and Atmospheric Administration (NOAA) and the Hadley Centre/Climate Research Unit in the UK. Data representing the lower troposphere temperatures was based on satellite microwave sensors.
“Our approach shows that the idea that the global warming trend has slowed or even paused over the last decade or so is a groundless misconception”, Rahmstorf says. The study has now been published in the Environmental Research Letters.
