Climate change is a chronic challenge – it is here now, and will be with us throughout this century and beyond. As the U.S. government’s National Climate Assessment report made clear, it’s already affecting people throughout the United States and around the world.
Warmer temperatures are making heat waves more intense, with harmful effects on human health. More intense rainfall and higher sea levels are leading to more frequent and intense flooding, with ensuing damages to property, infrastructure, business activity and health. Higher temperatures and strained water supplies are requiring new agricultural approaches, while fisheries are shifting and in some cases shrinking; in some cases, stressed food systems are contributing to national instability.
This reality means society needs to think about climate change in different ways than the past, by focusing on reducing the risk of negative effects. And speaking as a climate scientist, I recognize that climate science research, too, has to change.
Historically, climate science has been primarily curiosity-driven – scientists seeking fundamental understanding of the way our planet works because of the inherent interest in the problem.
Now it’s time for the climate science research enterprise to adopt an expanded approach, one that focuses heavily on integrating fundamental science inquiry with risk management.
Flexible infrastructure design
Climate risk management strategies need to be broad, ranging from efforts to reduce greenhouse gas emissions, to designing new infrastructure hardened against more frequent extreme weather, to policies that encourage development to shift to less exposed areas.
And these strategies must be flexible. In some cases, decisions made today affect people’s vulnerability for the rest of this century, even though there is much that remains to be learned about how climate change will unfold over the decades to come.
Consider the risks associated with sea-level rise.
The new rail tunnel under the Hudson River – if it is built – will likely still be in use in the next century. And yet, the scientific understanding of how much sea level will rise by the end of the century is quite imprecise. That’s because of uncertainty in how much greenhouse gases humans will emit and the immature scientific understanding of the ice-sheet physics.
It is possible – if emissions are high, and ice-sheet physics unstable – that the world could see 6 feet or more of global average sea-level rise over the course of this century, with substantially more in some regions. It is also possible – if emissions are low, or ice-sheet physics fairly stable – that it could be just 2 feet.
Ken Lund, CC BY-SA
If we as a society are making decisions that affect the world a century from now, we cannot blindly ignore either of these possibilities. If we treat 6 feet as a certainty, we could end up making unnecessary expenditures that come at the cost of other important priorities; if we treat 2 feet as a certainty, we may be putting lives and property at substantial risk.
So the best is an iterative approach. Communities can identify the resources and features that they value. Engineers and planners can identify key benchmarks – for example, critical levels of sea-level rise – that would require strategic changes to protect these values resources and features. And scientists can figure out what observations and theoretical insights would allow us to learn about those benchmarks as quickly as possible.
When the scientists discover that a benchmark is going to be hit – for example, when ice-sheet observations and modeling make clear whether we are on course for 2 feet or 6 feet of sea-level rise in this century – the engineers, planners and policymakers can adjust accordingly.