For the third year in a row, global average temperature records have been broken . Earth experienced the highest temperatures since we began keeping records back in 1880 and, compared to the average temperature of the 20th century (1901-2000), 2016 was nearly a full degree Celsius (0.94 oC) higher. Furthermore, since the beginning of the 21st century, average temperature records have been broken five times : 2005, 2010, 2014, 2015 and now again in 2016.
This is our new normal and, as Katie Dagon, a PhD candidate in the Department of Earth and Planetary Sciences at Harvard, points out, it is part of a global trend towards warmer averaged surface temperatures that climate scientists have already been observing. “One hot year is certainly significant, but the key is that for several years now, each year has broken the record of preceding years,” she explains.
But while record-breaking temperatures may have been somewhat normalized through sheer repetition, they are not harmless. The consequences of global warming are extensive, from an increase in the intensity of heat waves to rising sea levels. To counteract these effects and limit the advance of climate change, almost 200 nations signed the Paris Climate Agreement in December 2015. One of the agreement’s aims is to cap the increase in global average temperature below 2 oC .
Many climate scientists, however, believe keeping temperature increases below 2 oC is unlikely because it will require more than simply decreasing greenhouse gas emissions. “Carbon dioxide (CO2) lasts for a very long time in the atmosphere, because its absorption by long-term natural carbon sinks (e.g., plants, ocean, and soil which store CO2) is slow,” Dagon explains. “We have already built up high concentrations of CO2 in the atmosphere that have committed us to future warming.” Therefore, to reach the 2 oC goal, decreased emissions will have to be coupled with some form of “negative emissions” technology, that removes CO2 in the atmosphere. Lastly, for the Paris Climate Agreement to succeed, all nations will have to play a part in combating climate change, even those currently flirting with climate change denialism and “alternative facts”.
By NASA Goddard Space Flight Center from Greenbelt, MD, USA (2016 Climate Trends Continue to Break Records), via Wikimedia Commons
Special thanks to Katie Dagon for her expert commentary. Dagon wrote about negative emissions technologies such as geoengineering for SITN’s Dear Madam/Mister President Special Edition last year.