The Washington PostDemocracy Dies in Darkness

Opinion The world must take urgent measures to adapt to climate change. But that won’t be enough.

A kayaker fishes in Lake Oroville in California as water levels remain low due to continuing drought conditions on Aug. 22, 2021. (Ethan Swope/AP)

Adapting to climate change will be an existential imperative in the coming decades. That’s a key takeaway from a grim report released this week by the Intergovernmental Panel on Climate Change, the United Nations body dedicated to assessing global warming science. At times, the document feels like a surrender to the reality that massive losses from a warming globe are inevitable.

Unfortunately, adaption strategies are limited, the report warns. And relying too heavily on reactive strategies will place the greatest burden not only on vulnerable populations lacking the resources to adapt but also on the planet’s biodiversity. That creates an even greater need to double down on reducing greenhouse gas emissions while it is still possible.

The more than-3,500-page report is an exhaustive review of the devastating impact that climate change will have on the world — what U.N. Secretary General António Guterres described as “an atlas of human suffering.” Humans have already increased average global temperatures by 1.1 degrees Celsius (2 degrees Fahrenheit) since pre-industrial time. In the best-case scenario, in which humanity limits further warming to 1.5 degrees Celsius (2.7 Fahrenheit), the number of extreme weather events that a person born in the past decade will experience in their lifetime will increase nearly fourfold. Eight percent of the world’s farmland would become unsuitable for growing crops by the century’s end.

The bad news is that the world is on track to blow through that optimistic threshold. If that happens, the effects of climate change will become substantially worse. If, for example, the world warms by nearly 2 more degrees Celsius (3.4 Fahrenheit), the IPCC reports, tens of millions more people will experience extreme heat waves. Hundreds of millions more will be exposed to water scarcity. And millions more will die due to climate-related diseases.

Then there’s the effect climate change will have on wildlife. The report estimates that up to 14 percent of species in terrestrial ecosystems will likely face a “very high risk of extinction” if the globe warms 1.5 degrees Celsius. At 2 degrees, that rises to 18 percent. At 3 degrees, it’s 29 percent. Remember, many of these species are essential to human civilization. If they disappear, so will the pollinators that sustain our agriculture.

The report lays out a wide expanse of adaptive strategies to mitigate the effects of climate change, from structural measures, such as levees to hold back floods, to conservation strategies to protect ecosystems teetering on the brink. But these measures are limited. Many countries will not be able to afford to build adaptive infrastructure. And many fragile ecosystems — such as coral reefs and rainforests — are already nearing “hard limits” as they struggle to cope with warmer oceans or more frequent droughts.

It’s typical for reports such as this to be referred to as a “wake-up call.” But there is no excuse for policymakers to be asleep to the threat of climate change at this point. Time is running out to substantially reduce carbon pollution and other greenhouse gases. If we don’t act soon, adaptation will become impossible for many of Earth’s inhabitants.