The destruction by ISIS (Islamic State) of the ancient Assyrian city of Nimrud in Iraq and potential destruction of Palmyra in Syria has shocked the world—almost as much as the organisation’s previous beheadings of its captives.

Unfortunately, an article in this week’s New Scientist on sea level rise titled “Five Metres and Counting” (apologies print or paywall access only) suggests that climate change has already committed the world to the destruction of human heritage many orders of magnitude greater than anything ISIS is capable of doing.

You may be familiar with the Intergovernmental Panel on Climate Change (IPCC)‘s end of century sea level rise forecast (here, page 11 in the report). This pegs the upper sea level rise outcome at just below one metre (click for larger image).

What is less well-known is that this is just the preliminary phase of sea level rise. Given the extent of warming to date plus the warming guaranteed by current levels of carbon dioxide in the atmosphere, we are committed to barrel through one metre. In the words of Michael Le Page from The New Scientist:

Whatever we do now, the seas will rise by at least 5 metres. Most of Florida and many other low-lying areas and cities around the world are doomed to go under. If that weren’t bad enough, without drastic cuts in global greenhouse gas emissions–more drastic than any being discussed ahead of the critical climate meeting in Paris later this year—a rise of 20 metres will soon be unavoidable.

The arithmetic is pretty depressing (chart from New Scientist article): 0.4 metres for mountain glaciers, plus 0.8 metres for ocean thermal expansion, plus 3.5 metres for the West Antarctic ice sheet (the areas in orange in the chart below, click for larger image). If we go past 2 degrees Celsius of warming and get to 4 degrees, then we add all the blue bars as well.

Since the IPCC’s Fifth Assessment Report (AR5) was published, fresh evidence has emerged relating to West Antarctic ice sheet instability. Moreover, two large basins, the Aurora and the Wilkes, that form part of the East Antarctic ice sheet also appear vulnerable. In short, if we push up to 4 degrees Celsius of warming, then we are likely committing ourselves to 20 metre sea level rise.

So we’ve seen what ISIS had done in Nimrud, this is what we will do to Venice with 20 metres of sea level rise (source: here):

And New York:

These projections are Old Testament in terms of the scale of the catastrophes they portend; indeed, ISIS could only dream of unleashing such wanton destruction. Yet, in our failure to tackle climate change, such wanton destruction appears to have been accepted by the G20 elites and, frankly, ourselves.

Addendum:

Had a request for the background papers quoted by New Scientist. Most of these are behind paywalls but the authors frequently make pdfs available on their personal web sites or the web sites of their institutions:

Link to Science article on collapse of West Antarctic ice sheets

Click to access Science-2014-Sumner-683.pdf

Link to Nature Geoscience article on Aurora Basin (East Antarctic): http://www.nature.com/ngeo/journal/v8/n4/full/ngeo2388.html

Link to Nature Climate Change article on Wilkes (East Antarctic):

http://www.nature.com/nclimate/journal/v4/n6/full/nclimate2226.html

Link to Earth and Planetary Science Letters on overall East Antarctic melting (total 15 metres):

http://www.sciencedirect.com/science/article/pii/S0012821X14007961

Link to Nature Climate Change Letter on Greenland

http://www.nature.com/nclimate/journal/v2/n6/full/nclimate1449.html