Photo: Outdoor Workers Vulnerable to Climate Change

Photo: Climate change will compromise how brussel sprout seedlings are planted by farm workers in Santa Cruz, California.
Climate change will compromise global agricultural production and working outdoors.

If climate change continues as projected by the Intergovernmental Panel on Climate Change (IPCC), by mid-century, high temperatures and humidity are likely to compromise global agricultural production and working outdoors, according to the report from IPCC’s Working Group II released on March 25 in Yokohama, Japan. The IPCC identifies lost work capacity and reduced labor productivity in vulnerable populations among the top impacts from global warming if no major mitigation efforts are taken.

Agricultural and construction workers are some of the most highly exposed, say climate change experts from Working Group II led by Kirk Smith, one of two coordinating lead authors of the health impacts chapter. Smith is associate director for International Programs for COEH, professor of Global Environmental Health, director of the MS program in Global Health and Environment in the UC Berkeley School of Public Health, and the recipient of the 2012 Tyler Prize for Environmental Achievement.

“As time goes on, there will be more and more places in the world where you can’t work safely outdoors for a big part of the year, which results in a loss of productivity. Or an increase in health effects. Or both. You already see deaths from heat stroke, for example, in Central Valley and Central American farm workers.” says Smith.

The report, Climate Change 2014: Impacts, Adaptation and Vulnerability, focuses on three distinct time windows. “Are we seeing anything up to the present that can be associated with human-induced climate change, period two – up to mid-century and period three – past mid-century until year 2100?” asks Smith.

“It’s important to frame these three periods and the climate changes that may happen among them. You can’t go back and change the past,” he adds. “If you change what you do now, however, you start to see big changes about how much warming there is in the world past mid-century.”

Another emphasis of the new report is the attention to what Working Group II calls detection and attribution. Take an increase in tropical cyclones, says Smith. “Can we detect a signal appearing out of the noise, i.e., is the trend increasing beyond natural variations at the 95 percent confidence level?” The second question is attribution. “If you do see a change, is it due to human causes? To actually say that we are seeing more drought-related deaths, for example, than outside the range of natural variability, and then to say those are due to human-caused climate change, that’s a very strict criterion.”

The IPCC concludes that until year 2050 climate change will act mainly by exacerbating existing health problems. “Out to the period 2050, if things continue the way they are going – and there is no sign they’re not – the signal starts appearing out of the noise. If we don’t alter what we do, it’s very likely we’ll see an increase of health effects due to climate change. Not so dramatic that we couldn’t actually get ready for them through adaptation.”

Climate change is an incentive for providing basic public health services, argues Smith, such as clean water, food security, and social safety nets for the poor, emergency warning systems, vaccinations, and vector control. “These could greatly buffer humanity against the health impacts of climate change. But beyond the year 2050, in my opinion, is the most important reason to be worried about climate change. The world could be more stressful and risky for a lot of people, a place where there are not many conceivable adaptations.”

Smith notes one of largest potential impacts of climate change is on nutrition. “It’s pretty clear that there will be major impacts on agricultural production differentially around the world by 2050, but agricultural production is not equivalent to nutrition. Even in 2050, with impacts to the agricultural system, there will plenty of food around the world if we distribute it correctly. But we likely will not. On one hand, do we blame climate change, or do we blame poverty and poor governance? It’s hard to estimate how well the world will get its act together and provide that safety net. If we do, the impacts could be low. If we don’t, they could be very high.”

The IPCC honored Smith as one of roughly 800 authors worldwide who contributed to the Fourth Assessment published in 2007, which led to IPCC’s shared Nobel Peace Prize with Albert Arnold Gore Jr.

Look for more news on the health chapter of the just released IPCC Working Group II report (Impacts, Adaptation and Vulnerability) in The Lancet found at

Alistair Woodward, Kirk R. Smith, Diarmid Campbell-Lendrum, Dave D. Chadee, Yasushi Honda, Qiyong Liu, Jane Olwoch, Boris Revich, Rainer Sauerborn, Zoe Chafe, Ulisses Confalonieri, Andy Haines. “Climate change and health – the latest report from the IPCC,” The Lancet, 2014.

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