Sun, Sep 01, 2019 page7

• The oceans are turning from friend to foe, the UN warns

  Destructive changes could see a steady decline in fish stocks, a hundredfold increase in damage from superstorms and hundreds of millions of people displaced by rising seas

  • By Marlowe Hood and Patrick Galey / AFP, PARIS
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  The same oceans that nourished human evolution are poised to unleash misery on a global scale unless the carbon pollution destabilizing the marine environment is brought to heel, warns a draft UN report obtained by Agence France-Presse.

  Destructive changes set in motion could see a steady decline in fish stocks, a hundredfold or more increase in the damage caused by superstorms and hundreds of millions of people displaced by rising seas, according to a report on the oceans and the cryosphere, or frozen zones, by the Intergovernmental Panel on Climate Change.

  As the 21st century unfolds, melting glaciers would first give too much and then too little to billions who depend on them for fresh water, the report found.

  

  Illustration: June Hsu

  Without deep cuts to emissions, at least 30 percent of the northern hemisphere’s surface permafrost could melt by century’s end, unleashing billions of tonnes of carbon and accelerating global warming even more.

  The 900-page scientific assessment is the fourth such tome from the UN in less than a year, with others focused on a 1.5°C cap on global warming, the state of biodiversity, and how to manage forests and the global food system.

  All four conclude that humanity must overhaul the way it produces and consumes almost everything to avoid the worst ravages of climate change and environmental degradation.

  Governments meet next month in Monaco to vet the new report’s official summary. While the underlying science — drawn from thousands of peer-reviewed studies — cannot be modified, the diplomatic corps, with scientists at its elbow, plan to tussle over how to frame the findings, and what to leave in or take out.

  The final advice to policymakers is to be released on Sept. 25, too late to be considered by world leaders gathering two days earlier for a summit convened by UN Secretary-General Antonio Guterres to extract stronger national commitments in confronting the climate crisis.

  Guterres might be disappointed by what the world’s major greenhouse gas emitters put on the table, according to experts tracking climate politics in China, the US, the EU and India.

  The Big Four — accounting for nearly 60 percent of global fossil fuel-based emissions — all face devastating ocean and ice-related impacts, but none seem prepared to just announce more ambitious goals for purging carbon from their economies.

  US President Donald Trump — a no-show at the G7 climate segment this week — wants the US to exit the 2015 Paris agreement and has taken a chainsaw to former US president Barack Obama’s climate policies.

  India is rapidly developing solar power, but continues to build up coal-fired capacity at the same time.

  The EU is inching toward a mid-century “net zero” emissions goal, but several member states are dragging their feet.

  Long seen as a leader on climate, China — which emits nearly as much carbon dioxide as the US, the EU and India combined — is also sending mixed signals.

  “The eyes of Beijing are gradually moving away from environmental issues, and climate change in particular,” said Greenpeace International analyst Li Shuo (李碩), a longtime observer of China’s climate policy.

  A resurgence of domestic coal-fired power and a relaxing of air pollution regulations point to a preoccupation with China’s slowing economy and its trade dispute with the US, he said.

  Yet, all of these nations face many of the threats outlined in the panel’s report.

  For example, Shanghai, Ningbo, Taizhou and another half-dozen major coastal cities in China are highly vulnerable to sea level rise, which is projected to add a meter compared with the global watermark in the 20th century, if carbon dioxide emissions continue unabated. Mumbai and other coastal cities in India are in harm’s way as well.

  Even in the US, where billions are being spent to protect New York, Miami and other exposed cities, such efforts could easily be overwhelmed, experts have said.

  “There is a pervasive thread in the US right now promoted by techno-optimists who think we can engineer our way out of this problem,” Pennsylvania State University Earth System Science Center director Michael Mann said. “But the US is not ready for a meter of sea level rise by 2100 — just look at what happened in the wake of Superstorm Sandy in New York, or Katrina in Houston or Puerto Rico.”

  By 2050, many low-lying megacities and small island nations would experience “extreme sea level events” every year, even under the most optimistic emission reduction scenarios, the report said.

  By 2100, “annual flood damages are expected to increase by two to three orders of magnitude,” or 100 to 1,000-fold, it said.

  Even if the world manages to cap global warming at 2°C, the global ocean waterline would rise enough to displace more than a quarter of a billion people.

  This could happen as soon as 2100, although some experts think that it is more likely to happen on a longer timescale, the report said.

  “Even if the number is 100 or 50 million by 2100, that is still a major disruption and a lot of human misery,” said Ben Strauss, CEO and chief scientist of Climate Central, a US based research group.

  “When you consider the political instability that has been triggered by relatively small levels of migration today, I shudder to think of the future world when tens of millions of people are moving because the ocean is eating their land,” Strauss said.

  The average surface temperature has gone up 1°C since the end of the 19th century, and is on track — at current rates of carbon dioxide emissions — to warm another two or three degrees by the end of the century.

  The Paris agreement calls for capping global warming at “well below” 2°C.

  Sea level rise would accelerate rapidly moving into the 22nd century and “could exceed rates of several centimeters per year” — about 100 times more than today, the panel’s report said.

  “If we warm the planet by 2°C, by 2100, we will only be at the beginning of a runaway train ride of sea level rise,” said Strauss, whose research informs the report’s conclusions.

  Oceans not only absorb a quarter of the carbon dioxide emitted, they have also soaked up more than 90 percent of the additional heat generated by greenhouse gas emissions since 1970.

  In other words, without this marine sponge, global warming would make conditions intolerably hot.

  However, these obliging gestures come at a cost: Acidification is disrupting the ocean’s basic food chain and marine heat waves — twice as frequent since the 1980s — are creating vast oxygen-depleted dead zones.

  For example, in the Tasman Sea, a 2015 heatwave lasted 251 days, causing disease outbreaks and a die-off of farmed shellfish.
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