Banner image: Beachgoers cool off in the water at Bondi Beach in Sydney, February 2019. Australia’s coast dwellers must adapt to the inevitable effects of climate change. Joel Carrett/AAP.
A landmark scientific report has confirmed that climate change is altering the world’s seas and ice at an unprecedented rate. Australia depends on the ocean that surrounds us for our health and prosperity. So what does this mean for us, and life on Earth?
The Intergovernmental Panel on Climate Change (IPCC) findings were launched in Monaco on Wednesday night. They provide the most definitive scientific evidence yet of warmer, more acidic and less productive seas. Glaciers and ice sheets are melting, causing sea level to rise at an accelerating rate.
The implications for Australia are serious. Extreme sea level events that used to hit once a century will occur once a year in many of the world’s coastal places by 2050. This situation is inevitable, even if greenhouse gas emissions are dramatically curbed.
The findings, titled the Special Report on the Ocean and Cryosphere in a Changing Climate, strengthen the already compelling case for countries to meet their emission reduction goals under the 2015 Paris agreement.
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A rapid and dramatic cut in greenhouse gas emissions would prevent the most catastrophic damage to the ocean and cryosphere (frozen polar and mountain regions). This would help protect the ecosystems and people that rely on them.
The report entailed two years of work by 104 authors and review editors from 36 countries, who assessed nearly 7,000 scientific papers and responded to more than 30,000 review comments.
The picture is worse than we thought
Mountain glaciers and polar ice sheets are shrinking and, together with expansion of the warming ocean, are contributing to an increasing rate of sea level rise.
During the last century, global sea levels rose about 15cm. Seas are now rising more than twice as fast – 3.6mm per year – and accelerating, the report shows.
The IPCC’s projections are more dire than in its 2014 oceans report. It has revised upwards by 10% the effect of the melting Antarctic ice sheet on sea level rise by 2100. Antarctica appears to be changing more rapidly than was thought possible even five years ago, and further work is needed to understand just how quickly ice will be lost from Antarctica in future.
Key components and changes of the ocean and cryosphere, and their linkages in the Earth system. IPCC, 2019
If you live near the Australian coast, change is coming
By 2050, more than one billion of the world’s people will live on coastal land less than 10 metres above sea level. They will be exposed to combinations of sea level rise, extreme winds, waves, storm surges and flooding from intensified storms and tropical cyclones.
Many of Australia’s coastal cities and communities can expect to experience what was previously a once-in-a-century extreme coastal flooding event at least once every year by the middle of this century.
Our island neighbours in Indonesia and the Pacific will also be hit hard. The report warns that some island nations are likely to become uninhabitable - although the extent of this is hard to assess accurately.
Some change is inevitable and we will have to adapt. But the report also delivered a strong message about the choices that still remain. In the case of extreme sea level events around Australia, we believe a marked global reduction in greenhouse as emissions would buy us more than 10 years of extra time, in some places, to protect our coastal communities and infrastructure from the rising ocean.
Read the rest of the article on The Conversation here.