Thursday 17 October 2019

John Englander: 'Cities must follow Jakarta to avoid falling to rising seas'


Indonesian President Joko Widodo. Photo: Reuters
Indonesian President Joko Widodo. Photo: Reuters

John Englander

Indonesia made a stunning announcement this week that it will relocate its capital from Jakarta. The decision validates decades of warnings about the city's catastrophic flood risk due to sinking land and rising seas. While Jakarta is especially vulnerable to the threat of rising seas, it serves as a wake-up call for hundreds of major cities.

In making his decision, Indonesian President Joko Widodo said the city can no longer support its massive population in the face of environmental threats, as well as concerns of traffic congestion and water shortages. Top of his concerns is surely the fact the city is subsiding. In the past 30 years, Jakarta sank more than three metres, a problem made only worse as the world's great ice sheets melt.

Jakarta is an extreme case, but by no means unique. Although Miami is often cited as the city most at risk, there are many highly vulnerable - and highly populous -cities around the world, including Mumbai and Calcutta in India, Shanghai, Lagos in Nigeria, Manila, Dhaka in Bangladesh, Bangkok, Copenhagen, Tokyo, London, Houston and Tampa. In fact, thousands of coastal cities and rural communities globally are not only at risk, but already experience increased flooding during extreme high tides.

The swelling oceans demand we start designing for and investing in the future now. The latest projections for average global sea-level rise this century range from about one metre to as much as 2.5. Keeping it to the lower part of that range largely depends on extreme global efforts to reduce greenhouse gases far beyond current efforts. But even a 30cm rise in sea level can dramatically increase coastal flooding. Hundreds of millions of people are at risk.

Indonesia's decision to be proactive is something all coastal cities should do - what I call "intelligent adaptation". Instead of spending hundreds of millions on futile efforts to protect Jakarta from the dozen rivers which run through it - extending fragile walls never engineered to cope with the present threat - it will now start investing in a new capital city with a sustainable future.

Aggressively reducing carbon emissions could avert the worst scenarios, but sea-level rise probably cannot be stopped this century. The planet has already warmed 1C, meaning glaciers will go on melting for centuries.

Engineering for greater "resiliency" - the new buzzword - is a great idea to prepare for short-duration flood events such as from hurricanes. But preparing for rising sea level requires adapting to a new normal.

Coastal communities should be crafting 30-year masterplans to positively address the threat. For example, Washington is on the Potomac, a tidal river, and already experiences occasional flooding during extreme high tides and stormy weather. Rising seas will make that worse, but the city can probably protect itself with various forms of flood barriers.

Most vulnerable cities are not so fortunate. The sea is rising. We must rise with the tide.

© The Washington Post

  • John Englander is president of the International Sea Level Institute and author of 'High Tide on Main Street'

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