Health effects of climate change

The Lancet recently published the 2018 report on climate change and health, a 36-page document (see climate change and health. lancet2018 in dropbox, or doi.org/10.1016/ S0140-6736(18)32594-7).

Details:

-- they assessed 41 indicators across 5 domains: climate change impacts, exposures, and vulnerability; adaptation, planning, and resilience for health; mitigation actions and health co-benefits; finance and economics; and public and political engagement

-- this document included 27 leading academic institutions, the UN, and intergovernmental agencies from every continent

climate change impacts, exposures, and vulnerability

-- extremes of heat have steadily increased since 1990 in all regions, with 157 million more people exposed to heat wave events in 2017 vs 2000.

    -- Populations in Europe and the Eastern Mediterranean are particularly at risk with 42% and 43% of the populations older than 65 (the older populations there are why they are so at risk to the effects of heat exposure; other areas in the world with younger populations actually have more dramatic changes in extreme heat). The proportion of people around the world who are vulnerable to heat exposure is rising

-- 153 billion hours of labor were lost in 2017 because of heat, an increase of more than 62 billion hours since 2000. Notably the most hours of labor lost was concentrated in Central and South America, Africa, India, and Southeast Asia

-- the effects of climate change is not just heat, but extremes in weather: 712 extreme weather events resulted in $326 billion in economic losses, triple the total losses of 2016

    -- drought: increased exposure in larger areas of South America, northern and southern Africa, and Southeast Asia. Many areas having 12 months of drought throughout the year. Drought leads to premature mortality, reduced crop yields, food insecurity, and malnutrition. In addition there is increased spread of waterborne diseases (lack of potable water) and migration (reductions in habitable land)

    -- floods: 15% of all deaths related to natural disasters are from floods. In addition, there are longer term effects of spreading infectious diseases, increased mental illness, and increased destruction of infrastructure/homes/livelihoods. Extremes of heavy rain are most evident in South America and Southeast Asia.

        -- if we continue with our current situation, climate change is expected to result in an additional 1.4 billion drought exposure events per year and 2 billion flood exposure events per year by the end of the century

-- small changes in temperature and precipitation can result in large changes in the transmissibility of important vector-borne and water-borne diseases

    -- in terms of the vector capacity for the transmission of diseases:

        -- dengue fever: 2016 had the highest mosquito capacity on record, increasing to 9.1% for A. aegypti and 11.1% for A. albopictus (the dengue carriers)

        -- malaria: increased environmental suitability for Plasmodium falciparum in Africa and Plasmodium vivax in other regions, with the Highlands of sub-Saharan Africa having suitability for the mosquitoes increasing by 27.7% in the 2016 compared with the 1950s

        -- 24% increase risk for epidemics of Vibrio cholera in coastline area of the Baltics (Vibrio infections in general have been consistently associated with sea-surface temperature anomalies)

    -- also increases in malignant melanomas, another climate-sensitive disease

-- agricultural yield potential declined in every region; 30 countries had downward trends in yields reversing a decades-long trend to improvement [the graphs in the report are quite striking]

-- increasing sea surface temperatures is also resulting in decreased marine food security, in part related to coral bleaching from thermal stress

-- So, decreasing labor productivity, increasing capacity for the transmission of diseases such as dengue fever, malaria, and cholera, coupled with threats of food insecurity have already taken place, “compounding negative health and nutrition effects if temperatures continue to rise”

adaptation, planning, and resilience for health

-- the goal of a national health adaptation strategy/plan is to build the resilience of the existing health systems

-- current spending for climate change adaptation is well below the $100 billion per year commitment by governments under the Paris Agreement, and at that only 3.8% of this funding committed by the UN is dedicated to human health

-- overall there has been substantial decline in national health regulation capacities relevant to climate adaptation and resilience. This includes human resources (especially bad in the Americas, Eastern Mediterranean, Southeast Asia, and Western Pacific), surveillance capacity, and in preparedness capacity (though Africa still has the lowest preparedness capacity, this has been increasing more rapidly than in other areas)

mitigation actions and health co-benefits

-- mitigation efforts have stagnated in general: the carbon intensity of the total primary energy supply has not changed since 1990 (ie, despite more renewables, the intensity of carbon in our energy supply has not changed; which means “an ever-widening gap from the required path of rapid reduction towards zero emissions by 2050 to fill the Paris agreement”

-- CO₂ emissions leveled off from 2014 but have begun to rise again

-- coal use has declined since 2013, the preliminary data suggest that it might increase slightly in 2017 and 2018

-- and, currently, global employment in fossil fuel extractive industries is actually increased by 8% from 2016 to 2017, reversing a five-year downward trend (though coal use does continue to decline and more renewable energy was installed in 2017 than energy from fossil fuels)

--people in more than 90% of cities are breathing polluted air with fine particulate matter that is toxic to the cardiovascular and respiratory systems; between 2010 in 2016 air pollution concentrations worsened in almost 70% of cities around the globe

-- in 2015 fine particulate matter was responsible for 2.9 million premature deaths, coal being responsible for more than 460,000: almost 2 million in Asia, 130,000 in the Americas, more than 300,000 in Africa, and almost 500,000 in Europe. 

    -- eg see http://gmodestmedblogs.blogspot.com/2016/06/air-pollution-and-heart-disease.html for a review of some of these studies showing a strong relationship between air pollution and heart disease

    -- as a relevant aside (though not related to climate change), severe black lung disease cases has surged in the United States, after historic lows of the 1990s (the most severe forms were “nearly eradicated”, per the National Institute for Occupational Safety and Health). This is attributable to decreasing government regulation and increasing coal mining industry’s search to maximize their profits

-- ruminant meat consumption (i.e., basically from cattle) dominates greenhouse gas emissions from livestock, and has decreased marginally from 1990 to 2013

finance and economics

-- 712 climate related extreme events were responsible for $326 billion of losses in 2017, triple the losses of 2016

-- 99% of the losses of low income countries are uninsured

-- renewable energy in 2017 provided 10.3 million jobs, an increase of 5.7% from 2016; employment in fossil fuel extraction also increased to 11 million, an 8% increase form 2016

public and political engagement

-- global media coverage of health and climate change increased 42% from 2007-2017, but notably the increase was in health and climate change (4% increase/yr) but decreased for just climate change coverage (1.25%/yr)

-- there has been a 182% increase of health and climate change articles in scientific journals from 2007-2017, with more than 2500 articles assessing the links between the two.

--the UN General Assembly has increasingly linked climate change to health

Of note, China has been implementing some very positive initiatives:

-- the decrease in coal consumption is largely driven by China’s decreased reliance and continued investment in renewable energy

-- in 2017 more than 2 million electric vehicles are on the road; China is responsible for > 40% of electric cars sold globally

Commentary (many comments embedded above):

--the NY Times had an editorial a year ago or so, noting that in Africa and some other economically-poor areas, there is the double threat (perfect storm...): 

    --likely increasing population (augmented by Trump's ban on international family planning funding if there is any discussion of abortion), leading to closing of clinics/health care access: see https://www.theguardian.com/global-development/2017/jul/21/trump-global-death-warrant-women-family-planning-population-reproductive-rights-mexico-city-policy )

    --and, climate-change driven severe prolonged droughts decreasing access to water and food

    --all leading to increased likelihood of war for survival  between areas (and mass emigration, though i do not remember their mentioning that) 

    --yet another example of how the imposition of a really bad, anti-people policy could have dramatic long-term effects

--another issue not addressed in the above Lancet report is more specific to the science of climate change and our predictive models: an article in the February Scientific American (see Alley RB. Is Antarctica Collapsing?. SCi Am 2019 (February): 40-45) suggests that our models of glacier melting may be really underestimating its potential effects. he notes that the huge Jakobshavn iceberg in Greenland is receding at more than twice its original speed; this glacier has already led to sea-level rise; and this glacier is really really small compared to some very vulnerable ones in Antarctica (eg, the Thwaites Glacier Basin),which is projected by current models to increase sea-level rise by 11 feet!!! in the next century but in fact may be much faster (unclear. we need much more data/better understanding. but for this type of existential issue, one probably should not gamble for the better-than-worse-case scenario)

So, I realize I spend a lot of time writing about public health problems, such as antimicrobial resistance, changes in the microbiome, adverse social conditions which lead to important health problems, perverse incentives that support poor lifestyles, etc (though, notably, these problems are also man-made and basically preventable). But, the real bottom line is that climate change is “the biggest global health threat of the 21^st-century”, per this document. The effects are profound for all of us. And, it seems incumbent on us as health professionals to take a leading role in making sure that the population at large understands the considerable health effects of climate change (which are already happening), and that we mobilize our resources to help fight it.

geoff

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