(Salon) We Now Know How Badly Our Cities Will Be Flooded Due To Climate Change

Salon - Matthew Rozsa

Even if carbon emissions are curbed today, hundreds of millions will be displaced as vulnerable cities see flooding

A vehicle passes through a flooded street. All the major roads are flooded after the heavy rain during monsoon at Kolkata, West Bengal, India (Dibakar Roy/Pacific Press/LightRocket via Getty Images)

When it comes to climate change, the point of no return has already passed.

That is the message of a new report published in the esteemed scientific journal Environmental Research Letters.

It paints a picture of a future Earth in which, regardless of actions taken today, hundreds of millions of people will be displaced from their homes by rising sea levels. The carbon dioxide emissions already released into our atmosphere will linger for hundreds of years, warming the oceans and thus causing sea levels to rise. The only question now is whether the damage can be limited.

The answer, according to the report, is yes — but humans will need to take specific, drastic actions as soon as possible.

"Meeting the most ambitious goals of the Paris Climate Agreement will likely reduce exposure by roughly half and may avoid globally unprecedented defense requirements for any coastal megacity exceeding a contemporary population of 10 million," the authors write. (The report was co-written by Benjamin H. Strauss and Scott A. Kulp of Climate Central, DJ Rasmussen of Princeton University and German scientist Ander Levermann.)

The long-term goal of the Paris Agreement is to limit the mean increase in global temperatures to no more than 1.5°C above pre-industrial levels. Even if that happens, however, oceans will continue to swell, meaning there will be millions upon millions of drenched city dwellers.

"Roughly 5 percent of the world's population today live on land below where the high tide level is expected to rise based on carbon dioxide that human activity has already added to the atmosphere," Strauss told AFP. With roughly 7.8 billion human beings alive today, this means approximately 390 million currently live on land that will be under the high tide level as a result of climate change.

That said, reducing the temperature rise is crucial, experts say. If Earth's average temperature increases by even half a degree Celsius, an extra 200 million people will be vulnerable to the effects of sea level rise and increased storm surges. Each successive degree only increases the damage, as sea levels progressively rise and thereby displace more people.

In the report, the scientists offer detailed projections for the 20 most-affected large countries (those with at least 25 million people) in terms of the percentages of their populations that currently occupy land below high tide lines based on different warming scenarios.

If the planet merely warms by 1.5°C, 2.8 percent of the population of the United States could be directly impacted. Increase that by half a degree, and suddenly 5.9 percent of Americans could deal with rising sea levels. If it goes up by 3°C or 4°C, 7.9 percent or 9.9 percent of the American population could see rising sea levels where they live.

Things will be particularly bad in New York City, where officials are already considering sea walls and other measures to fortify its population against rising sea levels. Even under the most ambitious Paris Agreement target, land will fall under the high tide line that is currently home to 6.7 percent of the population. At 2°C, that rises to 13 percent; at 3°C, it reaches 19 percent; and at 4°C, it hits 28 percent.

The most vulnerable region, however, is Asia. Nine of the ten megacities at the highest risk are on that continent, and many of the countries with the starkest projections are also located there.

The jump from 1.5°C to 2°C makes the difference, in Vietnam and Bangladesh, between more or less than half of their total populations living below the high tide line.

If the planet's temperature rises to 4°C above pre-industrial levels, more than 60 percent of those nations' populations could fall below the high tide line.

More than 30 percent of the populations of Egypt, Thailand, Malaysia, the Philippines, Japan and Myanmar would also suffer that fate in a scenario where the temperature rises by more than 4°C.

Climate Central has also released visual illustrations of how prominent American landmarks will look after sea level rises. Almost all of the land around the Statue of Liberty National Monument will be submerged, as will the area surrounding Space Center Houston.

Yet these and other major landmarks would almost certainly have to be abandoned long before sea levels rose that high, as there will be an increase in heavy rainfalls and storm surges.

Links

• (Reuters) Climate Change Set To Worsen Resource Degradation, Conflict, Report Says
• (CNN) Germany's Deadly Floods Were Up To 9 Times More Likely Because Of Climate Change, Study Estimates
• (AU ABC) Climate Change Means More Floods, Fires And Heatwaves. Some Communities Are Already Adapting
• (Climate News Network) Flood Risk Will Rise As Climate Heat Intensifies
• (Reuters) Extreme Weather Renews Focus On Climate Change As Scientists Update Forecasts
• (USA NYT) Climate Crisis Turns World’s Subways Into Flood Zones
• (Reuters) From China To Germany, Floods Expose Climate Vulnerability.
• (Euronews) Experts: Europe Floods Show Urgency To Tackle Climate Change

(NYT) The Most Important Global Meeting You’ve Probably Never Heard Of Is Now

New York Times - Catrin Einhorn

Countries are gathering in an effort to stop a biodiversity collapse that scientists say could equal climate change as an existential crisis.

Opening ceremonies at the 15th United Nations biodiversity conference in Kunming, China, on Monday. Credit...Agence France-Presse — Getty Images

As 20,000 government leaders, journalists, activists and celebrities from around the world prepare to descend on Glasgow for a crucial climate summit starting late this month, another high-level international environmental meeting got started this week.

The problem it seeks to tackle: A rapid collapse of species and systems that collectively sustain life on earth.

The stakes at the two meetings are equally high, many leading scientists say, but the biodiversity crisis has received far less attention.

“If the global community continues to see it as a side event, and they continue thinking that climate change is now the thing to really listen to, by the time they wake up on biodiversity it might be too late,” said Francis Ogwal, one of the leaders of the working group charged with shaping an agreement among nations.

Because climate change and biodiversity loss are intertwined, with the potential for both win-win solutions and vicious cycles of destruction, they must be addressed together, scientists say. But their global summits are separate, and one overshadows the other.

“Awareness is not yet where it should be,” said Hans-Otto Pörtner, a biologist and climate researcher who has helped lead international research into both issues. He calls them “the two existential crises that humankind has elicited on the planet.”

Why biodiversity matters

Apart from any moral reasons for humans to care about the other species on Earth, there are practical ones. At the most basic level, people rely on nature for their survival.

“The diversity of all of the plants and all of the animals, they actually make the planet function,” said Anne Larigauderie, an ecologist who directs a leading intergovernmental panel on biodiversity. “They ensure that we have oxygen in the air, that we have fertile soils.”

Lose too many players in an ecosystem, and it will stop working. The average abundance of native species in most major terrestrial biomes has fallen by at least 20 percent, mostly since 1900, according to a major report on the state of the world’s biodiversity published by Dr. Larigauderie’s panel, the Intergovernmental Science-Policy Platform on Biodiversity and Ecosystem Services. An estimated million species are threatened with extinction, it found.

Former forestland in Kalimantan, Indonesia, on the island of Borneo, this year. Credit...Galih/Agence France-Presse — Getty Images

Climate change is only one driver of biodiversity loss. For now, the major culprit on land is humans destroying habitat through activities like farming, mining and logging. At sea, it’s overfishing. Other causes include pollution and introduced species that drive out native ones.

“When you have two concurrent existential crises, you don’t get to pick only one to focus on — you must address both no matter how challenging,” said Brian O’Donnell, director of the Campaign for Nature, an advocacy group. “This is the equivalent of having a flat tire and a dead battery in your car at the same time. You’re still stuck if you only fix one.”

How it works

This week, environment officials, diplomats and other observers from around the world gathered online, and a small group assembled in person in Kunming, China, for the meeting, the 15th United Nations biodiversity conference.

The United States is the only country in the world besides the Vatican that is not a party to the underlying treaty, the Convention on Biological Diversity, a situation largely attributed to Republican opposition. American representatives participate on the sidelines of the talks, as do scientists and environmental advocates.

Because of the pandemic, the conference has been broken into two parts. While this virtual portion was largely about drumming up political will, nations will meet again in China in the spring to ratify a series of targets aimed at tackling biodiversity loss. The aim will be to adopt a pact for nature akin to the Paris Agreement on climate change, said Elizabeth Maruma Mrema, the executive secretary of the convention.

Last year, officials reported that the world’s nations largely failed to achieve the targets of the previous global agreement on biodiversity, made in 2010.

If the new commitments are not translated into “effective policies and concrete actions,” Ms. Mrema said this week at the meeting, “we risk repeating the failures of the last decade.”

What’s next

The working draft includes 21 targets that act as a blueprint for reducing biodiversity loss. Many are concrete and measurable, others more abstract. None are easy. They include, in summary:

• Create a plan, across the entire land and waters of each country, to make the best decisions about where to conduct activities like farming and mining while also retaining intact areas.
• Ensure that wild species are hunted and fished sustainably and safely.
• Reduce agricultural runoff, pesticides and plastic pollution.
• Use ecosystems to limit climate change by storing planet-warming carbon in nature.
• Reduce subsidies and other financial programs that harm biodiversity by at least $500 billion per year, the estimated amount that governments spend supporting fossil fuels and potentially damaging agricultural practices.
• Safeguard at least 30 percent of the planet’s land and oceans by 2030.

A turtle that became caught in a fisherman’s net was released into the Watamu National Marine Park in Kenya last month. Credit...Brian Inganga/Associated Press

In the lead-up to the conference, that last measure, pushed by environmentalists and a growing number of nations, has received the most attention and resources. Last month, nine philanthropic groups donated $5 billion to the effort, known as 30x30.

“It’s catchy,” said E.O. Wilson, an influential biologist and professor emeritus at Harvard University. He said he hoped 30x30 would be a step on the way to one day conserving half of the planet for nature.

Indigenous groups have watched with hope and worry. Some welcome the expansion, calling for a higher number than 30 percent, while others fear that they will lose the use of their lands, as has happened historically in many areas set aside for conservation.

The debate underscores a central tension coursing through the biodiversity negotiations.

“If this becomes a purely conservation plan for nature, this is going to fail,” said Basile van Havre, a leader, with Mr. Ogwal, of one of the convention’s working groups. “What we need is a plan for nature and people.”

With the global human population still increasing, scientists say that transformational change is required for the planet to be able to sustain us.

“We actually need to see every human endeavor, if you will, through the lens of biodiversity and nature,” Dr. Larigauderie said. Since everyone depends on nature, she noted, “everyone is part of the solution.”

Links

• UN Biodiversity Conference (COP15)
• Our Response to Climate Change Is Missing Something Big, Scientists Say
• A ‘Crossroads’ for Humanity: Earth’s Biodiversity Is Still Collapsing
• Launch of IPBES-IPCC Co-Sponsored Workshop Report on Biodiversity and Climate Change
• There’s a Global Plan to Conserve Nature. Indigenous People Could Lead the Way.
• Nations Must Drop Fossil Fuels, Fast, World Energy Body Warns
• Medical Journals Call Climate Change the ‘Greatest Threat to Global Public Health’
• Afforestation of savannas: an impending ecological disaster (pdf)
• IPBES Global Assessment Report On Biodiversity And Ecosystem Services (pdf)
• Biodiversity: Finance and the Economic and Business Case for Action (pdf)