Following 2016’s record-breaking heat (the year marked a new record as regards global average temperature), and 2017’s already quite strange weather, we are now in “truly uncharted territory,” according to a new report from the World Meteorological Organization.
While 2016’s extremes can be partly attributed to the lingering effects of El Niño (how much? who knows?), 2017’s strange weather is harder to simply dismiss, as some may prefer to do. In particular, the state of sea ice extent in the Arctic and Antarctic is “alarming,” as the regions have been lingering at record-low levels or near-record-low levels for months now.
“Even without a strong El Niño in 2017, we are seeing other remarkable changes across the planet that are challenging the limits of our understanding of the climate system. We are now in truly uncharted territory,” commented David Carlson, the director of the WMO’s world climate research programme, as reported in The Guardian.
“Earth is a planet in upheaval due to human-caused changes in the atmosphere,” stated Jeffrey Kargel, a glaciologist at the University of Arizona. “In general, drastically changing conditions do not help civilisation, which thrives on stability.”
To build on that statement, the last time that the world was this warm was around 115,000 years ago, and the last time that atmospheric carbon dioxide levels were as high as they are now was around 4 million years ago. To explain what may seem at first to some to be a discrepancy there: it takes a while for the effects of atmospheric carbon dioxide levels to build to the point of their max temperature forcing — not all of the effects and activated feedback loops are immediate.
With that taken into account, it’s pretty clear at this point that the world’s ice caps aren’t likely to persist for more than a few hundred years (at the most), that the Arctic Ocean is likely to be free of sea ice within the near future. Additionally, a fast collapse of Greenland’s ice sheet is a real (and very dangerous) possibility.
“Arctic ice conditions have been tracking at record low conditions since October, persisting for 6 consecutive months, something not seen before in the (four-decade) satellite data record,” commented Prof Julienne Stroeve, at University College London in the UK. “Over in the southern hemisphere, the sea ice also broke new record lows in the seasonal maximum and minimum extents, leading to the least amount of global sea ice ever recorded.”
Emily Shuckburgh, of the British Antarctic Survey, commented as well: “The Arctic may be remote, but changes that occur there directly affect us. The melting of the Greenland ice sheet is already contributing significantly to sea level rise, and new research is highlighting that the melting of Arctic sea ice can alter weather conditions across Europe, Asia and North America.”
The Guardian adds: “Global sea level rise surged between November 2014 and February 2016, with the El Niño event helping the oceans rise by 15mm. That jump would have taken 5 years under the steady rise seen in recent decades, as ice caps melt and oceans get warmer and expand in volume. Final data for 2016 sea level rise have yet to be published.”
That’s quite “impressive” in a way. I’ve always been very skeptical of the rather conservative sea level rise predictions put out there by groups such as the IPCC. It’s looking pretty likely at this point that there will be significant sea level rise before the end of the century, regardless of any possible efforts to notably reduce global greenhouse gas emissions today or in coming years.