As Sea Levels Rise, Coastal Cities Face Flood Damage Exceeding $1 Trillion
By Tim Radford
By 2050, flood damage in the world’s coastal cities is expected to reach $1 trillion a year as sea levels rise and global warming triggers new extremes of heat, windstorm and rain.
More than 40 percent of these prodigious costs could fall upon just four cities—New Orleans, Miami and New York in the U.S. and Guangzhou in China.
Stephane Hallegatte of the World Bank in Washington and colleagues looked at the risks of future flood losses in the 136 largest of the world’s coastal cities.
Any coastal city is always at some risk—by definition it is at sea level, and often on an estuary or floodplain, and very often began as a seaport.
But risks increase as the environment changes: some coastal cities are subsiding; sea levels are slowly but surely rising as the oceans warm and the glaciers melt; and for two decades researchers have repeatedly warned that what used to be “extreme” events such as once-in-a-century floods are likely to arrive considerably more often than once a century.
But, Hallegatte and colleagues point out in Nature Climate Change, there is another factor: populations are growing, and even in the poorest nations there is greater economic development. At bottom, for any future disaster, there will be more potential victims, with more investment to lose.
In 2005, average global flood losses are estimated to have reached $6 billion a year. This figure is expected to grow to $50 billion a year, and unless cities put money into better flood defenses, losses could pass the $1 trillion mark.
To make their calculations, the authors matched average annual losses (and in a city like New Orleans, much of it already below sea level, this is estimated at $600 million) against a city’s gross domestic product, to provide a measure of how much should be set aside to pay for such losses.
Both New York and New Orleans have already undergone catastrophic flooding this century, and flood hazard can only increase.
Some cities—Amsterdam in the Netherlands is a classic example—are highly exposed to flood risk, and the once-a-century flood could cost the Dutch $83 billion, but in fact Dutch sea defense standards are probably the highest in the world. Ho Chi Minh City in Vietnam and Alexandria in Egypt have less to lose, but in relative terms both are far more vulnerable.
Prophecies such as these are intended to be proved wrong: the idea is that a prophet warns of horrors to come, people take steps and as a consequence the horrors do not arrive.
But as disaster professionals have learned again and again, governments, city authorities, investors and even citizens tend not to listen to prophecies of doom: scientists and engineers repeatedly described what could happen to New Orleans if it was hit by a powerful-enough hurricane, and in 2005, as Hurricane Katrina arrived, the levees gave way with catastrophic results.
But, the scientists warn, Miami, New York and New Orleans are especially vulnerable, because wealth is high but protection systems are poor, and governments should be prepared for disasters more devastating than any experienced today.
The paper’s authors argue that with systematic preparedness and adaptation, annual flood losses in the great global cities could be cut to $63 billion a year.
Engineering projects can help, but will not be enough, so civic authorities should also be thinking about disaster planning and comprehensive insurance programs to cover future losses.
Since risks are highly concentrated—any city piles millions of people and billions of dollars of investment into a relatively small area—flood reduction schemes could be highly cost-effective.
Visit EcoWatch’s CLIMATE CHANGE page for more related news on this topic.
- Redwoods are the world's tallest trees.
- Now scientists have discovered they are even bigger than we thought.
- Using laser technology they map the 80-meter giants.
- Trees are a key plank in the fight against climate change.
They are among the largest trees in the world, descendants of forests where dinosaurs roamed.
Pixabay / Simi Luft<p><span>Until recently, measuring these trees meant scaling their 80 meter high trunks with a tape measure. Now, a team of scientists from University College London and the University of Maryland uses advanced laser scanning, to create 3D maps and calculate the total mass.</span></p><p>The results are striking: suggesting the trees <a href="https://www.nature.com/articles/s41598-020-73733-6" target="_blank" rel="noopener noreferrer">may be as much as 30% larger than earlier measurements suggested.</a> Part of that could be due to the additional trunks the Redwoods can grow as they age, <a href="https://www.nature.com/articles/s41598-020-73733-6" target="_blank" rel="noopener noreferrer">a process known as reiteration</a>.</p>
New 3D measurements of large redwood trees for biomass and structure. Nature / UCL<p>Measuring the trees more accurately is important because carbon capture will probably play a key role in the battle against climate change. Forest <a href="https://www.wri.org/blog/2020/09/carbon-sequestration-natural-forest-regrowth" target="_blank">growth could absorb billions of tons</a> of carbon dioxide from the atmosphere each year.</p><p>"The importance of big trees is widely-recognised in terms of carbon storage, demographics and impact on their surrounding ecosystems," the authors wrote<a href="https://www.nature.com/articles/s41598-020-73733-6" target="_blank"> in the journal Nature</a>. "Unfortunately the importance of big trees is in direct proportion to the difficulty of measuring them."</p><p>Redwoods are so long lived because of their ability to <a href="https://www.nature.com/articles/s41598-020-73733-6" target="_blank" rel="noopener noreferrer">cope with climate change, resist disease and even survive fire damage</a>, the scientists say. Almost a fifth of their volume may be bark, which helps protect them.</p>
Carbon Capture Champions<p><span>Earlier research by scientists at Humboldt University and the University of Washington found that </span><a href="https://www.sciencedirect.com/science/article/pii/S0378112716302584" target="_blank" rel="noopener noreferrer">Redwood forests store almost 2,600 tonnes of carbon per hectare</a><span>, their bark alone containing more carbon than any other neighboring species.</span></p><p>While the importance of trees in fighting climate change is widely accepted, not all species enjoy the same protection as California's coastal Redwoods. In 2019 the world lost the equivalent of <a href="https://www.worldwildlife.org/threats/deforestation-and-forest-degradation" target="_blank" rel="noopener noreferrer">30 soccer fields of forest cover every minute</a>, due to agricultural expansion, logging and fires, according to The Worldwide Fund for Nature (WWF).</p>
Pixabay<p>Although <a href="https://c402277.ssl.cf1.rackcdn.com/publications/1420/files/original/Deforestation_fronts_-_drivers_and_responses_in_a_changing_world_-_full_report_%281%29.pdf?1610810475" target="_blank" rel="noopener noreferrer">the rate of loss is reported to have slowed in recent years</a>, reforesting the world to help stem climate change is a massive task.</p><p><span>That's why the World Economic Forum launched the Trillion Trees Challenge (</span><a href="https://www.1t.org/" target="_blank" rel="noopener noreferrer">1t.org</a><span>) and is engaging organizations and individuals across the globe through its </span><a href="https://uplink.weforum.org/uplink/s/uplink-issue/a002o00000vOf09AAC/trillion-trees" target="_blank" rel="noopener noreferrer">Uplink innovation crowdsourcing platform</a><span> to support the project.</span></p><p>That's backed up by research led by ETH Zurich/Crowther Lab showing there's potential to restore tree coverage across 2.2 billion acres of degraded land.</p><p>"Forests are critical to the health of the planet," according to <a href="https://www.1t.org/" target="_blank" rel="noopener noreferrer">1t.org</a>. "They sequester carbon, regulate global temperatures and freshwater flows, recharge groundwater, anchor fertile soil and act as flood barriers."</p><p><em data-redactor-tag="em" data-verified="redactor">Reposted with permission from the </em><span><em data-redactor-tag="em" data-verified="redactor"><a href="https://www.weforum.org/agenda/2021/03/redwoods-store-more-co2-and-are-more-enormous-than-we-thought/" target="_blank">World Economic Forum</a>.</em></span></p>
EcoWatch Daily Newsletter
- Offshore Wind Power Is Ready to Boom. Here's What That Means for ... ›
- American Skyscrapers Kill an Estimated 600 Million Migratory Birds ... ›
Kentucky is coping with historic flooding after a weekend of record-breaking rainfall, enduring water rescues, evacuations and emergency declarations.
<div id="0f31c" class="rm-shortcode" data-rm-shortcode-id="4290ab3e7ec4e142f8bce774bab39f03"><blockquote class="twitter-tweet twitter-custom-tweet" data-twitter-tweet-id="1366307788155219969" data-partner="rebelmouse"><div style="margin:1em 0">Just got back from my office... downtown Beattyville Kentucky is not a pretty sight. @KySportsRadio… https://t.co/6nXwyMKtRb</div> — Tom Jones (@Tom Jones)<a href="https://twitter.com/8atticus/statuses/1366307788155219969">1614588136.0</a></blockquote></div>
<div class="rm-shortcode" data-rm-shortcode-id="b41a2da6bf23cc19a5f38c2dc6c5f9fc"><div class="fb-post" data-href="https://www.facebook.com/dekalbtnfire/photos/a.924258171004562/3713119618785056/"></div></div>
Spring is coming. And soon, tree swallows will start building nests. But as the climate changes, the birds are nesting earlier in the spring.
- Spring Is Arriving Earlier Across the U.S. - EcoWatch ›
- Climate Change Leading to Fatal Bird Conflicts - EcoWatch ›
- The Unsettling Reason Why We're Seeing More Snowy Owls ... ›
Citigroup will strive to reach net-zero greenhouse gas pollution across its lending portfolio by 2050 and in its own operations by 2030, the investment group announced Monday.
- 20 Attorneys General Launch Climate Fraud Investigation of Exxon ... ›
- Exxon Plans to Increase Its Climate Pollution - EcoWatch ›
- Exxon to Slash 14,000 Jobs Worldwide as Oil Demand Drops ... ›