Professor Michael Mann, a climatologist, is the man whose famous hockey-stick chart put climate denial to rest. He has written a book called Our Fragile Moment about surviving climate crisis. Here’s why he is still hopeful about the future.
1. Earth’s climate is resilient to some extent
Climate models predict that Earth would have been frozen four billion years ago when the sun was only 70% brighter than it is now. It wasn’t. There were liquid oceans that were teeming with primitive life.
Carl Sagan’s solution to the “faint, young sun paradox” was that the greenhouse effects must have been greater back then. As the sun gradually grew brighter, the greenhouse effect decreased. This allowed the planet’s temperature to remain within a range that is habitable for life. The carbon drawdown was a result of the control that life exerts on the global carbon cycle.
This self-stabilizing characteristic of the Earth’s system is related to the Gaia Hypothesis, which was first proposed by James Lovelock and Lynn Margulis back in the early 1970s. It suggests that the Earth behaves like an organism and displays resilience as long as we don’t push it too hard.
2. The rumours about our doom have been greatly exaggerated
Climate deniers insist that it is too late to take action. They claim that we’ve triggered runaway global warming due to an unstoppable release in the atmosphere of methane as the Arctic permafrost begins to melt. They draw analogies with past major extinctions, such as the so-called “end permian” extinction or simply “the great dying” 250m years ago. This event was associated with the loss 90% of Earth’s species. They claim that the event was caused by a similar runaway heating event to what is happening today.
There’s no evidence that a massive release today of permafrost-methane, let alone a runaway warming. Paleoclimate evidence also does not support this interpretation of the ‘great dying’. We now know that the extinction was caused by the massive injection of carbon dioxide in the atmosphere through gigantic volcanic eruptions. This led to warming and ocean acidification.
We can limit the increase of carbon dioxide today, in contrast to the ancient release of carbon. This is done by reducing the burning of fossil-fuels.
3. The models are accurate
Some claim climate models vastly underestimate the rate of warming, and predict future changes. Paleoclimate data does not support this assertion.
Climate scientists measure the warming effects of greenhouse gases like carbon dioxide using what is called ‘climate sensitivities’. It is a measure for the warming that would result from a doubled concentration of carbon dioxide (something we might see in the future if policy does not change). We can estimate climate sensitivity by looking at past periods where carbon dioxide levels were similar, such as in the mid-Pliocene 3,0m years ago or the depths during the last ice ages 20,000 years ago.
The analysis of these past climate episodes reveals a climate sensitivity that is consistent with the most recent climate models. Climate models seem to get it right. The truth is enough, as I like saying. We don’t have to exaggerate science to motivate immediate action.
4. We are making progress
Another source of climate doomsday is the idea that we are making no progress when it comes to decarbonising the infrastructure of our society. It’s not true.
Prior to the Paris agreement of 2016, the world was facing a future warming of up to 4C if emissions continued as usual. Thanks to the progress being made in shifting from fossil fuels to alternative energy sources, global temperatures will likely stabilise at below 3C. If the nations of the globe keep their promises made at the recent global climate conferences, the warming will be kept below 2C.
Every fraction of a degree counts, even though it’s still too much warming. (There is widespread agreement that even above 1,5C we are at risk.) And while promises made are easier to keep than promises kept. We are making progress but it is not enough.
5. But there is also agency. There is urgency, but there is also agency.
The most famous extinction in Earth history occurred 66m years back when a massive asteroids struck Earth, killing all the dinosaurs.
We have no excuse, unlike the dinosaurs who were unable to see the future, let alone take action. We can see the metaphorical asteroid of the climate crisis approaching. It is a climate crisis that we have created and that we have thwarted.
The fossil fuel industry, in particular, has launched a massive campaign of disinformation to confuse the public and policymakers. We must therefore win the battle for hearts and minds and use our voice and votes to ensure that politicians are acting on behalf of people and not polluters. We can still keep the warming below the danger level of 1.5C. The obstacles aren’t technological or physical. The obstacles are entirely political. Political obstacles can be overcome by all of us if we are committed to acting. We can still preserve this fragile moment.
Michael E. Mann, a distinguished professor and director of the Center for Science, Sustainability and the Media, is based at the University of Pennsylvania, US. He is the author of Our Fragile Moment, How Lessons from Earth’s Past Can Help us Survive Climate Crisis.
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