landmark synthesis report today. The report—which summarizes findings released in Assessment Reports over the past year—underscores three major facts about climate change: It’s happening now, it’s already affecting communities and ecosystems around the world, and the most dangerous impacts can still be avoided if we act now.
The IPCC reports, released roughly every six years, are the most comprehensive, authoritative consensus on climate change among scientific experts. However, the cut-off date for literature for each Assessment Report was in 2013 , so it’s worth taking stock of recent scientific advancements and climate-related events that have occurred since then.
Here we discuss research highlights around four areas: sea level rise, extreme weather and climate events, ecosystems, and greenhouse gas (GHG) emissions and temperature. While by no means comprehensive, these findings illustrate how the trends documented in the IPCC continue to take a toll and in some cases, may be underestimated.
Sea level rise
- The Amundsen Sea portion of the West Antarctic Ice Sheet (WAIS) has reached a tipping point and is in the process of an irreversible collapse. Recent studies conclude that we are now committed to an additional rise in global sea level of more than 3 feet from the loss of this portion of the ice sheet alone.
- The northeast portion of the Greenland Ice Sheet (GIS), covering 16 percent of the entire ice sheet, was considered stable for approximately the last quarter of the 20th century. Recent analysis, however, determined that regional warming has contributed to this portion of the ice sheet melting at an alarming rate over the past decade. Average annual ice loss in the region between 2006 and 2012 was more than 10 Gigatons, or nearly the equivalent weight of 500 Great Pyramids. Considering the GIS is one of the largest contributors to global sea-level rise—and many models have not considered this area of the ice sheet in projections of global sea-level rise —this latest finding suggests a likely underestimate of future sea-level rise.
Extreme weather and climate events
- While the link between human-induced global warming and specific droughts, heavy precipitation and storm events analyzed in 2013 remains uncertain, there was overwhelming evidence linking human-induced warming and the severity and likelihood of 2013 heatwaves in Australia, China, Europe, Japan and Korea. These findings were part of the analysis undertaken by 20 different groups of scientists, which furthered the science of attribution of extreme events to human-induced climate change.
- The world experienced 261 weather-related disasters and a record 41 weather events that each caused at least $1 billion in damages in 2013, according to Climate Central.
- A study published this year shows that in dry years, the Amazon basin – which plays a critical role in absorbing greenhouse gas emissions-- loses carbon. If recent drought and fire trends persist, the Amazon may shift to become a source of carbon dioxide, further amplifying climate change.
- The National Audubon Society found that of 588 North American bird species studied, 314 will lose the majority of their current range by 2080 if global warming continues at its current pace.
GHG emissions and temperature
- According to data gathered at Mauna Loa Observatory in Hawaii, the daily average atmospheric concentration of carbon dioxide passed the 400 parts per million (ppm) mark in May of 2013 for the first time since measurements began. Before the Industrial Revolution, atmospheric concentrations of carbon dioxide were 280 ppm.
- Carbon dioxide emissions from fossil fuel burning and cement production were the highest in human history in 2013, and 60 percent higher than in 1990.
- Nine of the 10 warmest years on record have occurred since 2000. 2013 was the 37th consecutive year that annual global temperatures were above average, and so far the January-September period of 2014 is tied with 1998 as the warmest period on record.
A time for actionThe global scientific consensus represented by the latest IPCC report and recent scientific developments like those discussed above should sound an alarm bell. The impacts of climate change have transitioned from a theoretical and distant threat to a problem already affecting communities around the world today.
National leaders will be gathering in Lima, Peru in a few weeks to further negotiations towards a 2015 Agreement under the U.N. Framework Convention on Climate Change (UNFCCC). The recent science underscores the need for this Agreement to be a far-reaching success, as today’s actions will dictate the risks that we are forced to accept.