A resident of Louisville, Colo., walks through the remains of her childhood home on Dec. 31, 2021. A fast-spreading wildfire tore through several Colorado towns before burning itself out. JASON CONNOLLY - AFP - GETTY IMAGES

USA - I was a lead author on the climate report that won Al Gore the Nobel Prize. Here’s what we know now that we didn’t know then

What if we have been looking at climate change totally wrong? What if our greatest existential fear could instead offer hope for a brighter future?

Reports from the Intergovernmental Panel on Climate Change (IPCC), going back to 1995, have set the stage for how we think about climate change. First, climate impacts were thought to be a gradual and slowly increasing set of problems that would be manageable by well-understood technological and management processes. Second, mitigation was thought to be expensive and damaging to the economy. By that way of thinking, climate change would on balance be expensive to prevent and only moderately damaging.

As such, much of the motivation to respond has been driven by nonmarket considerations such as equity, the preservation of the natural world, and other benefits that are hard to price. As a lead author of the second and third IPCC reports, I understand this framework of beliefs quite well.

But what if these two core assumptions are wrong? What if the severity of climate change has been underestimated, and many of its harms are hard or impossible to adapt to? And what if the rate of potential technological progress is faster and the cost of alternative technologies cheaper than projected?

Then the fundamental economic equation changes, and decarbonization could be inexpensive compared to damages—or even benefit the global economy.

We likely live in that world.

How we got here

In the early days of climate science, research tended to focus on impacts far off in the future, at doubled preindustrial CO2 levels, often projected to the year 2100. Nearer-term projections were harder to characterize because the current climate is highly variable and scientists were conservative about projecting changes that were small relative to the system’s own variability. Many concluded that damages were far off in time and that socioeconomic systems would have time to adjust.

At the same time, those in the field being cautious (despite accusations of alarmism), projections of the cost of mitigation were quite high. Based on models from the early 2000s, assumptions about the rates of technological progress assumed slow rates of innovation. In fact, the challenge of mitigating emissions became associated with large expenditures and sacrifices, which would be a first for technological changes throughout history.

Since damages appeared to be far off, and mitigation costs high, the climate equation appeared to project a world where aggressive mitigation was expensive and thus unwarranted.

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