Heat Events and Climate Change: Challenges to the Occupational Physician

I continue to believe that despite recent setbacks, specifically the US withdrawal from the COP21 agreement, there will be a shift in thinking and a return to practical thinking in dealing with this most serious of global problems. I am posting here a modest contribution that was written in 2016 for my fellow physicians in occupational and environmental medicine. (This is why it reads a little dated.) This is a problem that cannot be wished away and so we have to learn to cope with it in our practice and the advise we give to enterprises, even in the absence of policy support at the federal level.

Climate change is real, it is progressing faster than expected, and it is changing or will change all aspects of human life from where we can live to what we can eat and at what cost. Everyone reading this blog is aware of climate change and so the details will not be repeated. The purpose of this piece is to describe how it will affect workers, the influence it will have on occupational health risk, and how we need to prepare ourselves as occupational physicians.

Climate change is closely linked to energy, technology, and economic activity. The root cause is that we have built our economies, our communities, and our agriculture on the foundation of fossil fuels that generate carbon dioxide, which is the main (but by no means only) greenhouse gas. Despite abundant warnings and research, we failed to act when we could and now the concentration of carbon dioxide in the atmosphere has committed us to centuries of elevated mean temperature and extreme fluctuation in weather, with the consequences that will go with it. It is too late to stop temperature rise and we can only try to keep it short of levels that would trigger catastrophe.

The environmental consequences of climate change are profound and well publicized. The occupational health implications less so and this is what we will focus on.

Some industries will not do well as climate change progresses. For some industries, this is because the consequences will raise risks, as for agricultural workers exposed in the fields and construction workers. Other industries will be affected because of the economic dislocations and restructuring which have already started. Coal, being the major source of carbon dioxide emissions, is already in precipitous decline. Oil and particularly gas will not face the same existential threat but will be curbed. Tourism may become untenable in hot places or where storms are frequent.

The most vulnerable working populations will be outdoor workers (most obviously in agriculture and construction). The communities in which workers live will be faced with threats such as food insecurity and arthropod-borne infectious disease. Wealthy countries such as the US have the means to adapt and to get the food they need. These problems could devastate much of the rest of the world., families living with limited economic means or access to air conditioning, and those predisposed to hyperthermia (the very old, the very young, pregnancy, and preexisting medical conditions.

For workers, this usually means cardiovascular disease or medication, and lack of fitness.

Surveys conducted in 2014 on members of the American Thoracic Society by George Mason University (Virginia) reported that 77% of practitioners believed that climate change was already affecting their patients, mostly from allergies, adverse weather events, and heat, especially those with asthma or COPD.

OSHA, NIOSH, and other agencies have adopted recommendations for managing heat stress in outdoor workers. The elements of a heat stress program are consistent in the recommendations: provide shade, abundant clean water to drink, cooling rooms (for prevention and for emergency management of workers entering or at risk for heat stroke), air conditioning in vehicles, rest periods, a buddy system on hot jobs (no isolated work), watchful monitoring for signs of heat stress, and avoiding peak temperatures during the day. These measures are really a minimum program for every hot worksite. Individual measures that workers can take include reducing obesity, abundant hydration, and avoiding alcohol and drugs of abuse. However, prescription drugs may also predispose to heat stroke, such as antihypertensive and cardioactive drugs.

On an enterprise level, the occupational physician may find the issue of climate change challenging. Management and clients may be skeptical and resistant to preparing for heat stress if the risk is framed as a response to climate change. Occupational physicians are not recognized as experts in climate change or even universally recognized as expert in heat stress. Thus, it is usually better to address the problem as a contingency plan for weather variability, as part of an emergency plan, or good occupational health practice. When senior management seems receptive to a direct discussion on climate change, it can be tied to business continuity of operations, the company disaster plan, the corporate sustainability policy, and, as always in occupational health, recent tragedies or other publicized events.

On a broader community and global scale, workers will be faced with serious consequences in their home communities, an example of the “double burden” of exposure at work and in the home. Unfortunately, there is little that an individual occupational and environmental physician can do beyond the worksite , advocating in communities, and exercising a citizen’s voice. Effective action requires coordination and passion, and at the moment we are stuck. Some familiarity with the background issues and vocabulary help to make advocacy more effective.

That climate is changing around the world is clear: mean temperatures are getting warmer, extremes (hot and cold) are swinging more widely, and short-term weather patterns are changing in ways we generally do not like and will like even less in the future. 2016 has been the hottest year in the human experience. A series of complicated secondary events result from this warming trend, including ice melt, rising sea level, changing storm patterns, and changing precipitation patterns (drought and inundation, in different places). The “nightmare scenario” is that there will be a change in ocean currents, which stabilize continental climate patterns.

The frequency, duration, precipitation, and power of adverse weather events reflects and underlying changing in the energy budget of the atmosphere, driven by retained heat due to forced enhancement of the “greenhouse effect”, without which life could not exist on Earth. The forcing is due to emissions of greenhouse gases, particularly but not exclusively, carbon dioxide, mostly from fossil fuel combustion. This is why the problem of global climate change is intimately linked to energy policy choices and technology and to economic activity. The anthropogenic addition of additional greenhouse gases to the atmosphere, especially carbon dioxide, ensures that the greenhouse gas effect will be exaggerated for centuries to come. On top of this average warming pattern are additional cycles: the seasons, broad temperature “oscillations” in the Pacific Ocean

This is not news. The last ten years returned controversy to what had been a largely settled issue among scientists, that the climate was beginning to change around the world due to human activity. However, what seemed to be understood in the 1990’s as settled science was surprisingly reversed in the 2100’s, as increasingly strident and partisan voices questioned whether climate change, which was becoming obvious, was caused by human activity, of “anthropogenic” or, in some cases, whether it even existed. This doubt was contrary to evidence and the virtually unanimous opinion of climate scientists but it was enough to delay effective response. In effect, by holding back on action, we and painted ourselves into a corner. The relatively short window we once had to mitigate greenhouse gas emissions without major economic and social dislocations opened and closed. We went from 300 ppm, past the safe target of 350 without a blink and are currently at 400, which is scarily close to the 450 estimated to the tipping point for irreversible global change, at least for the duration of the human species. 

To some extent, economic incentives for clean energy, side-benefits of pollution control, and broader social trends toward sustainability kept progress in reducing carbon emissions from stopping entirely. However, by itself the reconstruction of industry and the energy sector and the tepid regulatory response to date have not been enough. It is clear that valuable, perhaps irretrievable, time has been lost. We traded relatively straightforward options that had many side benefits in reducing pollution and diversifying energy sources in which the few options left involve unproven technologies or risky engineering on a planetary scale, often called “geoengineering” and widely feared even among technocrats. Having blown past our best opportunity to bring things out of control, future action will be more expensive, more disruptive, more uncertain of success, and fraught with unanticipated consequences.

One has to believe that we will muddle through somehow but thus far we have been very good at making things more difficult for ourselves.

(c) 2017, Tee L. Guidotti.