The seas are rising; there is no question about that. A new study suggests the increase in sea levels could be as much as 1.3 meters (a little over 4 feet) by the end of this century or it could be half of that. It all depends on what happens to the ice in Antarctica and that depends on how much coal is burned over the next few decades, according to a new paper published in the journal Environmental Research Letters.
If the world continues to burn as much coal as it does today, that 1.3 meter rise is pretty much guaranteed, the author, Alexander Nauels of the University of Melbourne, says. If it is reduced so that less than 5% of the world’s electricity comes from burning coal by 2050, the increase in sea levels could be limited to around 2 feet. To see what effect rising oceans would have on various world cities, visit the interactive mapping tool online at Geology.com. Below is a view of New York City if sea levels increase by 1 meter.
The report, covered by The Guardian (where we found out about it), confirms that significant sea level rise is inevitable and requires humans to adapt rapidly. But the study reveals the majority of that rise — driven by newly recognized processes on Antarctica — could be avoided if the world meets the commitment made in Paris to keep global warming to “well below 2°C.” The study uses simplified physical models that allowed the researchers to explore all known contributions to sea level rise and pair them with the new generation of emissions scenarios the Intergovernmental Panel on Climate Change (IPCC) will use in its next set of reports.
The study finds global sea levels will rise by an estimated 1.32 meters if nothing is done to limit carbon pollution. That’s 50% more than the current report from IPCC predicts. It suggests the current carbon reduction pledges the nations agreed to reach by 2030 at the COP21 climate conference in Paris are so weak they will require very deep cuts between 2030 and 2050 to avoid triggering significant melting in Antarctica.
Nauels and his colleagues used next generation of emissions scenarios that include assumptions about socioeconomic factors such as energy demand, energy generation, population growth and GDP. Those scenarios suggest coal can only make up 5% of the world’s energy mix by 2050 if sea level rise is to be limited to around 2 feet. To achieve that result, a global carbon price higher than $100 per ton will be required.
Nauels says the work done by his team assumed Antarctica would contribute to sea level rise, but that more research is needed, as reported by The Guardian. “We still have to find out what’s going on in Antarctica. We can’t base all future sea level rise projects on just one paper. And the Antarctic ice sheet community are frantically working on the new insights.”
Robert DeConto, a climatologist at the University of Massachusetts Amherst, wrote a report in 2016 predicting that Antarctica could contribute to massive sea level rise much earlier than thought. He is encouraged by the study by Nauels. “In the aggressive mitigation pathways, where we assume that the global community gets its act together and we reduce emissions, it’s a much rosier picture. There’s a much reduced risk of dramatic sea level rise from Antarctica. This study fully reinforces that.”
So, if you believe humanity can forge cooperative alliances to meet existential challenges with prudent and thoughtful action, we’re going to be all right. But if you are a student of history, there is precious little reason to be optimistic.