Rising sea levels: what’s the truth?

Where I live in the former county of Huntingdonshire is a long way from the sea. But according to some predictions of sea-level rise, it could be a lot closer soon.

In one scenario, with widespread inundation of the Fens, Cambridge could virtually become a coastal city by 2050. London, Cardiff, Blackpool and Hull could all be severely affected. Scenarios like these are alarming and make great media headlines, but what is really going on?

Causes and effects

Sea-level rise is already an observable phenomenon. As glaciers and ice sheets in Greenland and the Antarctic melt due to global warming, there’s extra water in the oceans. TV images of calving icebergs are all too familiar, and scientists worry that even if warming stopped tomorrow, we may be passing a tipping point where ice loss becomes irreversible. Oceans are also great heat stores, but at warmer temperatures water becomes less dense and expands, further adding to sea level rise. If you live in the south or east of England, you get a triple whammy as the land is already gradually sinking into the sea for entirely unrelated reasons. Insurance companies are seriously worried, not just because the City of London is in a high-risk area.

The UN Intergovernmental Panel on Climate Change (IPCC) predicts the worst possibility is a 1.1 metre rise by 2100. That’s a fairly conservative figure; other studies predict 2.5 metres even if the goals of the Paris Agreement on climate change are met. It doesn’t sound a lot, but it could wipe out some small island states. A rise of only 50 cm means that Bangladesh may lose about 11% of its land, affecting an estimated 15 million people living in its low-lying coastal region.

At higher levels of global warming it gets worse. One study estimates that, at three degrees of global warming, 275million people worldwide live in areas that will eventually be flooded, mostly in major Asian cities such as Shanghai, Hong Kong and Osaka, but with devastating global impacts.

God’s promise

Christians may wonder if it’s time to build an ark. Well, someone’s already done that in Kentucky, but hurry, places are limited. More seriously, we might have questions like: ‘Is God judging the world again?’ or ‘What about God’s promise to Noah that there would never again be a flood to destroy the earth?’ (Gen. 9: 11).

There have been many devastating floods in modern history. The 1931 floods on the Yangtse River in China are supposed to be one of the most destructive, with estimates of several million deaths. But even the most extreme scenarios for sea-level rise don’t predict the wiping out of the entire human race. I think we can safely say, even without confidence in God’s character as a promisekeeper, that His promise to Noah is not at risk.

That’s not to say there’s no element of judgement in this. You could argue that, by polluting the atmosphere, humanity has brought potential disaster on itself. I think we should be alarmed by the prospect, and although the more extreme scenarios may not come to pass, they should act as a wake-up call. Although it was initially done in ignorance, we now know enough to put things right if we act quickly.

Christians can be confident that ‘The Lord sits enthroned over the flood; the Lord is enthroned as King for ever.’ (Ps. 29:10). This knowledge shouldn’t lead us to be stoical, but to work hard to avert a crisis and alleviate suffering, trusting that the Lord is sovereign.