According to climate experts, this would result in a surface temperature increase of 4.8°C over the period 2081-2100 as against the average for 1986-2005, a rise in sea levels of almost one metre, the proliferation of extreme climate events (such as droughts, torrential rainfall and stronger hurricanes), together with worsening food insecurity. Measurements at the Mauna Loa Observatory in Hawaii went up by more than three parts per million (ppm) in 2015. The spike is due to a combination of human activities and the El Nino weather pattern.