California’s heatwave ranking law, and the global heat-response struggle

California’s heatwave ranking law

To much media fanfare in early September – while the U.S. west sweltered under a grueling weeks-long record-setting heatwave – California governor Gavin Newsom signed into law a set of bills intended to soften the increasing financial and social impact of deadly weather. Among the newly signed bills is the nation’s first law establishing a heatwave raking and early-warning system. In other words, heatwaves will be ranked according to their possible effect on people, much as hurricanes get a 1 to 5 rating, based on a maximum sustained wind speed.

The bill is noteworthy for California and important for the rest of us because, in the past, California’s environmental legislation has set trends. What’s more, the new law comes as global conversations are turning to ways, we, as a human society, can help protect people against heat extremes.

According to a press release from Newsom’s office:

The legislation builds on California’s Extreme Heat Action Plan [PDF here] released earlier this year. [It’s] an all-of-government strategy to strengthen the state’s resilience and mitigate the health, economic and ecological impacts of extreme heat, which fall disproportionately on the most vulnerable Californians.

Heatwave ranking and public health

The new laws in California are due to go into effect on January 1, 2023. And the California Environmental Protection Agency will have two years to produce the heatwave ranking system. The ranking system is supposed to take into consideration reliable weather forecasts and historical data and “measures of extreme heat severity,” as well as information on microclimates in California, and public input.

And it’ll try to address the effects of extreme heat on public health, which many scientists agree needs more study. Meanwhile, there’s general agreement that, as a 2017 study of heatwaves and health in the UK put it:

… Deaths are expected to increase due to hotter temperatures.

And that’s especially true among vulnerable populations, such as the poor and elderly.

But how will the California laws fit with responses to global warming that the rest of the world is proposing and attempting? Does the world need to coordinate its response to extreme heat, as the world warms?

Do rankings need global cooperation?

The UN’s World Meteorological Organization (WMO) seems to think a global response to a warming world is the way to go. In July 2022, the WMO issued a policy statement regarding heatwave ranking systems that begins with this:

The top priority of the World Meteorological Organization and its members is to save lives through accurate forecasts and early warnings. A very successful example of this, in recent years, is improvements in Heat-Health Early Warnings and Heat Action plans, underpinned by strong collaborations between the meteorological, health, disasters management, and scientific communities.

Yet they go on to say that, by creating its own ranking system, California might be muddying the waters unintentionally:

Independent practices to rank and name heatwaves which are not coordinated with the official warning systems, may risk disrupting civil protection protocols and coordination efforts, bring unintended negative consequences, or reduce the effectiveness of established heat advisory and response measures.

Something has to be done … But what?

There is, of course, little if any opposition to easing the impact of extreme heat on people. The evidence shows that heatwaves can be deadly. But, in this early stage of humanity’s attempt to cope with ongoing global warming, disagreement exists on what approaches will work. The Adrienne Arsht-Rockefeller Foundation Resilience Center is leading an international effort to give heatwaves names, like those hurricanes and typhoons receive. The group says naming heatwaves will allow authorities to respond more appropriately to them when they occur and to plan for them in advance.

And maybe that’s true. But, most importantly, the organization maintains, naming heatwaves would spur vulnerable members of the public – not just the infirm or elderly – to protect themselves:

Recent research finds that younger people are susceptible to heat-related illness as well – no one is safe in the heat. In August 2021, a young couple hiking in California died on the trail amid triple-digit [Fahrenheit] temperatures, making headlines and underscoring the central contradiction: people do not perceive themselves to be at risk, even during life-threatening conditions.

To that end, the organization has started pilot programs to name heatwaves in Athens, Greece and Seville, Spain. The WMO, however, is urging caution about the scheme, as forecasting the intensity and affected areas of heatwaves is an as-yet imprecise science:

Forecast-based naming creates additional challenges that named events might not actually take place, might turn out to be less severe, or occur in different localities. This could potentially undermine any benefits of raised awareness through naming and create false alarms.

The WMO suggests pilot programs to name heatwaves work closely with the officials in charge of extreme heat responses to avoid confusion and interference.

And, still, it’s getting warmer

Last week’s reporting on California’s new heat response lauded it as the first of its kind in the nation. But – for those close to the world of science, those who lived for many decades in one place, or for anyone who is just paying attention – it’s been clear for at least 40 years that global warming is real and ongoing. According to the latest reporting by the International Panel on Climate Change [PDF here], each of the last four decades was hotter than the previous one since 1850.

Moreover, the IPCC reports, people are driving the change and have been for about 270 years:

Observed increases in well-mixed greenhouse gas concentrations since around 1750 are unequivocally caused by human activities.

And the problem of rising global temperatures appears to be eating away at economic productivity, according to an October 2021 study published in Nature Communications:

For the analysis of current impacts, we focused on heatwaves occurring in four recent anomalously hot years (2003, 2010, 2015, and 2018) and compared our findings to the historical period 1981–2010. In the selected years, the total estimated damages attributed to heatwaves amounted to 0.3–0.5% of European gross domestic product (GDP). However, the identified losses were largely heterogeneous across space, consistently showing GDP impacts beyond 1% in more vulnerable regions.

The study says the problem could become far worse:

Future projections indicate that by 2060 impacts might increase in Europe by a factor of almost five compared to the historical period 1981–2010 if no further mitigation or adaptation actions are taken, suggesting the presence of more pronounced effects in the regions where these damages are already acute.

But this news isn’t new. Another study published in Science and dating back to 2004 predicted that areas already susceptible to heatwaves will be even more at risk as the 21st century progresses:

Model results for areas of Europe and North America, associated with the severe heatwaves in Chicago in 1995 and Paris in 2003, show that future heatwaves in these areas will become more intense, more frequent, and longer lasting in the second half of the 21st century.

Bottom line: In September 2022, California passed a law requiring a heatwave ranking system by 2025. But does the world need to coordinate its response to extreme heat?

Authorities are struggling to coordinate responses to extreme heat events that are occurring with more regularity and greater intensity.