Note: This and several subsequent posts will be about possible adaptations to climate change. Serious consideration of adaptations does not require any slackening of effort to mitigate climate change. We’ll start with the sea levels.Background: If all the ice on land were to melt (mostly Antarctica), then sea level would rise about 220 feet. If all sea ice melted (mostly in the Arctic), sea levels wouldn’t rise but, without human intervention, a lot of animals that depend on the sea ice to hunt will certainly go extinct (e.g. polar bears, ring seals). It is currently predicted sea levels will rise that 1 to 4 feet and end-of-summer Arctic Sea ice could disappear by 2100.
What types of adaptations would be necessary to reduce the damage to humans and the rest of the biosphere? Starting with humans, what have been some tried-and-true approaches to defend against sea encroachment and its side effects? Here, per Wikipedia, is what the Dutch have done:
“Natural sand dunes and human-made dikes, dams and floodgates provide defense against storm surges from the sea. River dikes prevent flooding from water flowing into the country by the major rivers Rhine and Meuse, while a complicated system of drainage ditches, canals and pumping stations (historically: windmills) keep the low lying parts dry for habitation and agriculture. Water control boards are the independent local government bodies responsible for maintaining this system.”
Okay, so they didn’t build the natural sand dunes – but engineering could figure out reasonable substitutes in the form of levees and seawalls. Of course, none of these are completely disaster-proof (e.g., most seawalls were overwhelmed during the 2011 earthquake and tsunami in Japan). And there are trade-offs (e.g., eyesores and erosion). But limitations and trade-offs are part of every engineering project. You don’t just give up in the face of imperfection – you keep trying to do the best possible job and then continue to adjust the process as new knowledge and technology become available.
Engineering solutions would have to be complemented by maintaining and enhancing coastal ecosystems. For instance, wetlands and reefs play a critical role in “reducing the vulnerability of coastal communities to rising seas and coastal hazards, through their multiple roles in wave attenuation, sediment capture, vertical accretion, erosion reduction and the mitigation of storm surge and debris movement.” (Spalding et al;, 2014). Some islands and coastal areas may be able to increase the height of the ground.
A lot of people will still need to move inland, to higher ground, or off the island. By 2050, about 3.7 million people in the US alone may need to migrate away from coastline and areas vulnerable to storm surges and rising rivers. Over a longer course of time, we will see much greater migration away from vulnerable areas (Manhattan?). For the US, such migration is manageable – there will still be plenty of empty space (currently at 35 people per kilometer). The US could also take in many more people from other countries, where there is little room for internal migration, such as Bangladesh.
None of this is to deny the likely down-side of large-scale migrations or the immense suffering of those who are forced to migrate. Migrations will bring about a host of new issues to deal with, including effects on the international order, global economy, and agriculture. That’s why advance planning and problem-solving are so important. Anticipation is half the battle.