Ann Arbor (Informed Comment) – In a new paper, Chris R. Stokes et al. write in Communications Earth and Environment that even if we manage only to heat up the earth 1.5º C. (2.7º F.) above pre-industrial norms, that might be enough to provoke massive melting of the world’s principal ice sheets — those in Greenland, East Antarctica and West Antarctica.
The previous academic consensus was that it would take an increase of 3º C.(5.4º F.) to melt them. But Stokes and colleagues find that the ice sheets are more vulnerable to global heating than had been previously thought. They write,
“Here we synthesise multiple lines of evidence to show that +1.5 °C is too high and that even current climate forcing [temperature increase] (+1.2 °C), if sustained, is likely to generate several metres [yards] of sea-level rise over the coming centuries, causing extensive loss and damage to coastal populations and challenging the implementation of adaptation measures.”
Since at the moment the world is on a trajectory that will certainly shoot past 1.5º C., and probably will take us close to 3º C. by the end of the century, these findings are very bad news. Because when the ice sheets melt, the water goes into the oceans and causes them to rise. In addition, the world’s glaciers are also melting, and this surface ice is also contributing to rising sea levels. Finally, warmer water expands to fill more volume, which also contributes to sea level rise, and the oceans are heating up rapidly.
And if the world’s seas rise more and faster than we had anticipated, that development is in turn very bad news for people who live in low-lying coastal areas and cities. Bad, as in their houses are foreordained to be under water before too long and they will have to relocate, perhaps in the hundreds of millions, inland.
Stokes & co. explain, that the latest projections from the UN’s climate science panel (IPCC) are that melting from the world’s major ice sheets could raise sea levels by as much as 1 foot, 2 inches by the year 2100 if we significantly reduced emissions.
But if emissions remain very high, they say, the increase could be more like 4.7 to 20.5 inches, that is, up to a foot and a half.
And if we look out 175 years, and if humanity are all assholes like Donald Trump and ExxonMobil CEO Darren Woods, we can’t rule out a sea level rise of over 10 meters / 30 feet. It has been remarked that the future seems really far away but the past seems near. So 175 years ago is only 1850, when American Express was founded, the gas mask was patented, refrigerator-made ice was first produced, Los Angeles was incorporated and California became a state. My maternal grandfather was born in 1887 and knew a lot of people alive in 1850, and I in turn knew him well. So 175 years from now isn’t so far off — if you are young, your great-grandchildren may be alive. They won’t be living on the coast, or not on the coast as it is now constituted.
The authors say that a billion people now live on land less than 30 feet above sea level, and 230 million people live on land less than 3 feet above sea level. At our current rates of burning coal, fossil gas and petroleum, if we got 8 inches or so of sea level rise by 2050, the world’s largest 136 coastal cities would suffer $1 trillion per year of losses. They also make the point that it isn’t just the absolute amount of sea level rise that will be challenging, but how fast things will change. Every day we’ll be waking up to a new crisis, which will make adaptation difficult.
They also look at evidence from past geological eras, where sea levels were much higher than today even though the concentration of carbon dioxide in the atmosphere was lower than ours (we’re at 431 part per million of C02).
So, in short, earlier modeling and projects by climate scientists were way too conservative on this issue. It isn’t a slam at the scientists, who conscientiously always gave lower and higher values for their projections. It is just that there seem to be feedback loops of which they were unaware, and which are still not perfectly explained, so that the upper levels of their predictions are the ones that now seem most plausible.
So just to make this discussion a little more concrete, I think we should look at Egypt. Like the parts of Louisiana stretching down to New Orleans, Lower Egypt is a river delta — the result of the build-up of silt into soil at the mouth of the Nile, just lifting the land above the level of the Mediterranean. It stretches 150 miles along the Mediterranean coast, and from just north of Cairo 100 miles to Alexandria on the coast.
Photo of a bridge near Alexandria by Mustafa ezz: https://www.pexels.com/photo/orange-concrete-bridge-surrounded-by-water-1059965/
Alexandria has seen rising sea levels seep up beneath the foundations of its buildings. Whereas building collapses were once rare, since 2015 some 40 buildings a year have just fallen down.
The city has lost 40% of its beaches since 2000, in part because of sea level rise.
Eman Munir writes that sea level rise is already affecting “parts of Alexandria, Beheira and Kafr El-Sheikh governorates.”
In Kafr al-Sheikh governorate [province], some villagers on the coast have already lost land. Erosion and sea level rise are only part of the problem. Storm surges cause salt water to invade the low-lying farms near the Mediterranean, salinizing the land and making it infertile. He quotes Saeed Umair, “When the sea rises here in the winter, it causes terror among people. At first the sea swallowed one piece, then a piece and a half. My father’s land used to be vast and green, producing a significant harvest every year. We could sustain our lives and provide for our children from it. I had hoped to continue what my father started, but the sea overwhelmed us. The land became saline, and there is no drainage to remove the salinity. The crops died, and the palm trees died too.”
Some 60 million people now live in the Egyptian Delta. Will they have to move house, some of them even by 2050? Where would that many people go? Upper Egypt’s geography and agricultural potential is such that it couldn’t support them. They would overwhelm Sudan if they moved that far up the Nile — its population is only 50 million now, and 16 million are in danger of starving to death because of ethnic and ideological warfare.
Aridification and lack of water will drive some wars in the Middle East over the next century. But too much water will drive others. All because we are addicted to carbon, which we have made our graven idol.
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