Tipping Points
Climate Change Tipping Points
This is Dr. Mark Trexler with today’s Climate Countdown, exploring climate change tipping points. What are they, and why should we all care?
You may have heard about tipping points that could trigger feedback loops that could worsen climate change. Scientists have been talking about such tipping points for many years. What you may not know is that today’s climate models and forecasts generally don’t account for them because there’s no scientific consensus on when they might be triggered, and to what effect.
The tipping point you’ve probably heard the most about is the potential collapse of ice sheets in Greenland and West Antarctica. In fact, we may have already triggered that tipping point, and 40 feet of sea level rise, but this particular tipping point could take centuries to fully play out.
Several other tipping points may also have already been triggered. We’re well on our way to an ice-free summer arctic, for example, leading to significant changes in the region’s weather, and substantially increasing how much heat is absorbed into the Arctic ocean.
Some observers also think we’ve reached a tipping point in the ability of some boreal and Amazon ecosystems to absorb carbon. If those forests have switched from being net sinks to being net sources of carbon, CO2 concentrations in the atmosphere will rise more rapidly, accelerating temperature increases.
Other tipping points are harder to sort out. Some scientists argue, for example, that the Atlantic Gulf Stream is slowing down as a result of climate change. If it shuts-down, the global effects would be dramatic. Much of Europe would, ironically, get much colder.
Then there are some truly frightening tipping points that, at least in principle, could be triggered at any time, with catastrophic implications. For example, there are enormous quantities of carbon and methane stored in Arctic permafrost, as well as on the ocean floor. With temperatures rising, permafrost is melting, oceans are warming, and some scientists think we’re already starting to see the release of some of that carbon and methane. If those releases start picking up steam, it could lead, for all practical purposes, to virtually uncontrollable climate change. This is the kind of scenario that underlies discussions of how the earth could potentially warm by a catastrophic 6 degrees Celsius or more this century.
There are other tipping points in play, but you probably get the idea.
The real question is, if tipping points are so potentially dangerous, why aren’t climate models and climate policy discussions taking them more seriously? Simply put, the lack of a scientific consensus leads us, quite inappropriately, to psychologically discount their importance. It’s a great example of what Margaret Heffernan was talking about when she noted that, “In failing to address climate change, all the forces of willful blindness come together like synchronized swimmers in a spectacular water ballet.”
What is indisputable, however, is that as greenhouse gas concentrations in the atmosphere, and average global temperature, continue to rise, the likelihood of triggering or accelerating the workings of these tipping points is increasing. The result could be uncontrollable climate change, yet most of our climate conversations today are limited to discussing the global targets of 1.5 and 2 degrees C.
Even with no scientific consensus, the possibility of triggering these tipping points, no matter how small the probability, should be keeping us up at night. That’s not happening, and it’s just one more example of how our response to climate change differs from so many other risks that we routinely manage.
This is Mark Trexler with the Climate Countdown. Access more information on today’s topic at our website climatecountdown.climatesites.net. And thanks for listening.