The average global temperature increases steadily. Based on the analysis of three independent time series the American National Oceanic and Atmospheric Administration (NNOA) found that in 2016 the average surface temperature was on average 0.95°C higher than in the 20th Furthermore, the NNOA’s research found that 16 out of the 17 warmest years on record took place since the year 2000. In the four decades since 1977 no year had an average temperature lower than the 20th century average. (Source: NNOA)
The human made greenhouse effect – caused by increasing emissions of CO2 and other greenhouse gasses – is responsible for this development. A metanalysis of 4,014 scientific articles on climate change concluded that 97% of publications and 98% of authors make out human activity as the direct cause of climate change. (Cook et al. (2013), Quantifying the consensus on anthropogenic global warming in scientific literature. Environmental Research Letters, 8, No. 2).
The glaciers of Greenland and Antarctica contain enough water to raise the sea level by up to 60 meters. During a period of slightly increased average global temperatures approximately 125.000 years ago, a reduction in ice caused an increase in sea levels of 6 to 9 meters. A similar scenario threatens costal areas worldwide today again (Source: National Snow and Ice Data Center).
However, the increased temperatures alone are not the problem. Global warming increases vaporization rates across land and oceans leading to heightened levels of atmospheric humidity resulting in more regular and intense rainfalls and storms. Such extreme weather phenomena have increased in regularity during the recent decades (Source: Lehman et al. (2015), Increased record-breaking precipitation events under global warming. Climate Change, Vol. 132, No. 5; Kossin, James P. (2013), Trend Analysis with a New Global Record of Cyclone Intensity. Journal of Climate, Vol. 26).