Editor’s note: This is the first part of a four part series we will be publishing in the coming weeks reviewing some of the important developments in the field of sustainability in 2016. We start with a review of the temperature records that were set in 2016 and the increasing evidence that climate change is directly contributing to extreme weather events. Part 2 of this series can be seen here and Part 3 here.
In 2016, the global average temperature reached the highest level in recorded history. According to the World Meteorological Organization (WMO), temperatures for 2016 reached 1.2 degrees centigrade above pre-industrial levels, with consecutive record highs from May to December. While El Niño caused temperature anomalies early in the year, even after accounting for that impact, NASA’s Goddard Institute for Space Studies (GISS) showed that there has been overall warming when contrasted to years with similar conditions. This rise in global average temperature after accounting for such temperature anomalies is illustrated in Figure 1.
Data from the National Oceanic & Atmospheric Administration (NOAA) Earth System Research Laboratory’s Global Monitoring Division showed that atmospheric carbon dioxide (CO2) also reached a record high in 2016 at 407.7 parts per million (ppm) in May 2016. This continues a trend of annual increases in monthly mean CO2 concentrations as illustrated in Figure 2. High atmospheric carbon concentration means that there are more heat-trapping greenhouse gases in the atmosphere, which leads to further warming.
Figure 1. Global annual average temperatures anomalies (relative to 1961-1990), Source: WMO 
Figure 2. Atmospheric carbon dioxide concentrations in ppm, Source: NOAA
The consequences of a warmer climate, driven by increases in CO2 concentrations, were made very clear in 2016. For their respective times of year, maximum winter sea ice extent reached record lows in March, as did snow cover in April, and sea ice extent in October . This is perhaps best seen in the loss in mass of the Greenland land ice sheet, shown in Figure 3, which as of February 2016 recorded a loss of 3540 gigatonnes (Gt) in contrast to 3273.3 Gt in February 2015.
Figure 3. Greenland mass variation since 2002, Source: NASA
Mass variation is perhaps best depicted in north-eastern Greenland, or the Kronprins Christian Land peninsula. Figure 4 shows changes in land ice sheet mass in December for the years 2000, 2008, and 2016. Mass variation as a result of ice melt is perhaps one of the most directly visible signals of a warming climate.
Figure 4. Land ice sheet variation in north-eastern Greenland, Source: Google Earth with data from Landsat/Copernicus
Two consequences of ice melt include increasing frequency and magnitude of extreme weather events and sea level rise. Satellite data by the NASA Goddard Space Flight Centre showed that change in sea level peaked in March 2016, at 88.6 millimetres sea height variation, a considerable rise from March 2015 at 80.3 millimetres. Sea level rise threatens populations living in coastal areas, an impact that is resoundingly clear in places like the Marshall Islands, where large swaths of land are becoming uninhabitable due to floods, droughts, and storms. Small Island Developing States are especially at risk, not only due to increased exposure to the consequences of sea level rise, but unable to afford extensive adaptation measures like seawalls.
In terms of extreme weather events, three countries experienced the most intense events in their history: Fiji (Cyclone Winston), Seychelles (Cyclone Fantala), and Typhoon Lionrock (DPRK). The flooding that came as a result of Typhoon Lionrock was especially destructive, placing 600,000 in food and water insecurity with the interruption of water supply and the inundation of arable land. Other notable extreme weather events in 2016 included continued droughts in such places as Viet Nam, where 83% of the country is being affected by drought according to the Food and Agriculture Organization (FAO) of the United Nations. There have also been record-setting floods in the Yangtze basin (China, since 1999), Ganges basin (Sri Lanka), and the Mopti (Mali, since 1964).
Overall, 2016 was a continuation in the decades long trend of warming that climate scientists have been documenting since the late 1980s. However, as the frequency of extreme weather events in 2016 showed, as the earth moves further outside of the temperature range that has been stable for the last 10,000 years the consequences will become more severe and more frequent.
Image courtesy of Flickr. Originally published by S&S on March 8, 2017.