Column: Patience

Back in March, when the COVID-19 pandemic was just starting to turn the world upside down, I decided to focus my writing, for this column and Physics Today‘s Search & Discovery department, on other topics. The media landscape was already flooded with COVID-related content on everything from the mathematics of epidemic models to the chemistry of hand soap. There didn’t seem to be much for me to add.

Then, on 26 March, I read a piece by Kelsey Piper at Vox.com, and I thought, “Why didn’t I write that?”

Piper made what seemed to me an obvious point: It takes at least a few days for someone newly infected with COVID to show symptoms, a few more days to get a test—if there are tests to be had at all—and a few days after that to get the test results back. New COVID cases showing up in the statistics on 26 March probably represented individuals infected two or more weeks earlier, before stay-at-home orders had gone into effect anywhere in the US. It would take time to see the results of our efforts to fight the virus.

Miller’s Diary

Physics Today editor Johanna Miller reflects on the latest Search & Discovery section of the magazine, the editorial process, and life in general.

Obvious as it may have been, it needed to be said. Across the US, individuals and communities were being forced to make sacrifices greater than almost anything in living memory—shuttering businesses and offices, pulling children out of school, losing jobs, losing health insurance—yet the numbers of new COVID cases kept climbing at a dizzying rate. It felt like nothing was working and all our efforts might be in vain. But as Piper noted, it’s important not to give up too soon. “Our greatest enemy,” she wrote, “is our own impatience.”

And apparently, it still needs to be said, so I’ll say it again. Case numbers may rise for a while after a mitigation measure (business shutdown, stay-at-home order, or mask requirement) is put in place; that doesn’t mean the measure isn’t working. And case numbers may fall for a while after the measure is lifted; that doesn’t mean that lifting it was harmless. Furthermore, any change in the trend won’t show up on the first day that the case numbers could possibly be affected; it takes another week or two, at least, to see that the curve is being bent. For the lagging indicators—hospitalizations and fatalities—it takes longer still.

Which is to say: Waiting to act until the situation is truly alarming is waiting too long.

It’s frightening to see what’s going on in the southern and southwestern US right now, with many of the governors of those states acting like all is well just because their hospitals aren’t overwhelmed yet. Even elsewhere, though, the trends are worrisome. My home state of Maryland, like other northeastern states, beat back the first wave of COVID this spring with aggressive mitigation measures, but we relaxed those measures too soon and too quickly, encouraged by our falling case and hospitalization numbers. If we’d been just a little more patient in reopening, we might have suppressed the virus to the point where our testing and contact-tracing capacities could have kept it at bay. Before too long, though, our case counts stopped falling, and now they’re rising again. I hope our state and local leaders have a plan to reverse that trend, but I worry that they don’t.

And that’s not the only thing I’m worried about.

Last week I read a paper in Nature Communications titled “Delayed emergence of a global temperature response after emission mitigation.” The paper, by a trio of researchers at the CICERO Center for International Climate Research in Oslo, Norway, cites two others, one from PNAS and the other from WIREs Climate Change. All three papers make broadly the same point: The time lag between taking action against climate change and seeing a difference in the global surface temperature isn’t weeks, months, or years, but decades.

Even if greenhouse emissions could be abruptly cut to zero, it would take the better part of 10 years to notice any difference; for any realistic mitigation pathway, it could take 30 years or more.

Much of the delay is due to natural fluctuations in the climate system. The global mean surface temperature bounces around from year to year, no matter what we do, so it takes a while to discern a change in the long-term trend. There’s a good chance, as the WIREs Climate Change paper showed, that even with mitigation measures in place, the planet could warm more quickly over the next 15 years than it did over the previous 15. And because there’s only one Earth, there’s no control group—no way to directly see that if we hadn’t cut emissions, temperatures would have risen faster still.

Thirty years is a long time. In the US, it’s seven presidential election cycles, and seven more midterm congressional elections. That’s 14 times our leaders will be called to account for their policies, and 14 chances for the public to register their impatience with the sacrifices they’re being asked to make without seeing any payoff. Even if the US manages to implement an effective climate policy in the first place, what are the chances that such a policy will survive all 14 cycles?

“This paper is about managing our expectations,” say the Norwegian researchers. I admire their intentions, but have they met my compatriots?