A cold shower of reality. This is 2020. Few of us will be here in 2100, but this is not just because we don’t all expect to live for another 80 years.
Very few of us will be here in 2100 simply because large parts of here will be going, going, gone — along with many of the houses, roads, businesses and fields we know so well.
Rising sea levels may not seem to be an urgent problem — and, anyway, we are supposed to have a coastal defence plan. But our grandchildren are also likely to have a lesson in nature’s exponential arithmetic.
It seems increasingly unlikely that climate warming will be constrained to +2℃. The current Paris Agreement (+1.5℃ target) is already seen as inadequate and unlikely to be achieved. The plan assumes, of course, that every country will stick to their international agreements to limit global warming. How likely is that?
The latest observations suggest that the rate of sea-level rise may double every 20 years.
This year’s rise in sea level may not seem very much at all. But, as it rises faster, year on year, the cumulative effect is huge. 5mm a year in 2020 becomes an extra 1cm/p.a. in 2040 and, by 2100 the rate will be accelerating by +8cm every year.
That adds up to a lot of extra water — between 1 to 2 metres. It adds up to a lot less habitable land, more local islands, probably a growth in ferry services, no skiing holidays, many more beaches and houses built on stilts. And that doesn’t count inland flooding from extreme weather events, also triggered by climate change.
‘The last time our world was a couple of degrees warmer — during the Eemian interglacial 125,000 years ago — sea level was between six and nine metres higher than it is today.’ — Prof. William J McGuire, UCL
London is currently protected by the Thames Barrier. It was designed and built as an urgent response to the UK’s East Coast flood of 1953 — a catastrophic combination of high tides and poor weather. When completed in 1982 the barrier was expected to be needed perhaps twice a year. Last year the barrier was raised 9 times. It will be useless once the sea level has risen more than 2 metres. Some pundits may suggest that the Eemian is a poor guide to the future, arguing that there is little symmetry between the heating of the poles, but recent Antarctic observations provide little comfort.
Meanwhile, here on the UK’s South coast, the local plan to hold back the waves is, apparently, stalled while people argue about which latter-day Cnut might pay for it. There’s no sign yet of any plan to retreat from low-lying places around here, but, if we were interested, there’s a wealth of experience to be found in Asia and southern parts of the USA. Alternatively, we might, perhaps, gain some time if our governments realise that their aspirations to achieve net-zero emissions by 2050 will achieve far too little, far too late.
Like glaciers, time is melting away. Governments and large organisations are rarely good at sustaining long term plans. Sustainability is an individual choice. Each of us must now choose the life we leave to our grandchildren.