© BJ Kirschhoffer/Polar Bears International
10/15/2018 4:29:50 PM
New U.N. Climate Report Rings Alarm Bells and Provides Guidance
By Dr. Steven C. Amstrup, Chief Scientist
Ninety-one of the world’s leading experts on global warming have just provided a report showing us that we must act now to bring a halt to carbon emissions if we care about our future. The U.N. report on climate change also shows we still have time (although not much) to avoid a climate catastrophe. Finally, the authors describe a path for achieving success.
Among the report’s conclusions:
- Human uses of carbon-based fuels already have warmed the world about 1° Celsius (1.8° Fahrenheit), with news-making consequences for people and ecosystems.
- Although impacts of rising temperatures frequently occur along a continuum, many serious thresholds will be crossed as the world warms from 1.5° C to 2° C (3.6° F). Most important, the authors show how a 2° C warmer world will be unlike the climate that has allowed humans to flourish.
- Aggressive mitigation, including measures to capture and store carbon, can keep warming below 1.5°
- Taxes on carbon emissions, coupled with dividends that return revenues to consumers, appear the most workable implementation path toward a 1.5° C temperature limit.
Half a degree, big difference
In 2010, my colleagues and I predicted that remaining on a business as usual carbon emissions path would lead to the extirpation of polar bears from approximately two-thirds of their current range by mid-century and to more dramatic reductions in their numbers by century’s end. Our current emissions path differs little from what we examined in 2010. Without action, the world will shoot by a 1.5° C average temperature rise by mid-century and hit about 4° C (7° F) by century’s end—with serious consequences for polar bears and the rest of us.
A difference of just half a degree Celsius turns out to be critical for polar bears. In a world that is 2° warmer, every third summer in the Arctic is likely to be ice-free, leaving the bears without access to their seal prey. Imagine if your grocery store closed for half of every third year and you had no way to stockpile food from the other two years. Clearly, polar bears and other wildlife that depend on sea ice would struggle to survive in such a scenario. In contrast, a temperature rise of 1.5° brings just a 3 percent chance of an ice-free summer in the Arctic, which is much more manageable.
But it’s not just about polar bears, and it’s not just about the Arctic. This report makes it clear that if we allow the world to warm 2 or more degrees, humanity will face so many challenges that no one will be talking about polar bears. Societies will be grappling with the impacts on humans of droughts, massive storms, enormous wildfires, and refugee crises that dwarf anything we’ve seen.
Setting a price on carbon
The report also shows, however, that it’s still possible to limit global warming to 1.5° above pre-industrial times—half a degree above the current average. But reshaping our energy use will take a concerted effort by world leaders and unprecedented cooperation. An important conclusion of the report is that establishing a price for carbon emissions, along with a dividend payment back to consumers, may be the best way to accomplish that transformation.
Such plans, in which “the more you pollute, the more you pay, and the less you pollute the more you gain,” provide a level playing field for the whole energy sector and will allow market forces to guide carbon reductions without partisan wrangling. Such a plan provides people with new ways to make money while they are helping save the world.
Coincidentally, two researchers who showed the value of carbon taxes in arresting global warming won this year’s Nobel Prize in economics, adding impetus to the findings of this report.
Polar Bears International has long embraced carbon tax and dividend plans. We welcome this guidance from the international community and will continue to push for a transition to that path forward.
Probability that September Arctic sea ice extent drops below 1 million km2 (referred to as “ice-free”) as projected by the Community Earth System Model, a state-of-the-art climate model, under two scenarios reaching 1.5 and 2 degrees Celsius global mean warming, respectively, in the second half of the 21st century. See Sanderson et al. (2017, Earth System Dynamics, DOI: 10.5194/esd-8-827-2017) for more details.