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to household air pollution, largely arising from use of
solid fuels, such as coal, wood, charcoal, and biomass,
for cooking.
Efforts to provide clean cooking and heating tech- tor, continue to contribute substantially to burden of
nologies could result in substantial health co-benefits
in addition to reducing greenhouse-gas emissions
and short-lived climate pollutants. Exposure to
ambient air pollution, most importantly fine par-
ticulate matter (PM), constitutes the largest global
Downward trends in
global yield potential for
all major crops tracked
since 1960 threaten food
production and food
security, with infants
often the worst affected
by the potentially
permanent effects of
under nutrition
environmental risk factor for premature mortality,
and results in several million premature deaths from
cardiovascular and respiratory diseases every year.
TODDLERS AFFECTED
More than 90 per cent of children are exposed to
PM concentrations that are above the WHO guide-
lines, which can affect their health throughout their
life, with an increased risk of lung damage, impaired
lung growth and pneumonia, and a subsequent risk of
developing asthma and chronic obstructive pulmo-
nary disease.
Most of the exposure to PM results from anthropo-
genic activities, and much of this is associated with
combustion of coal and other fossil fuels for electric- ter wheat, and soybean has reduced in concert with
ity generation, industrial production, transport, and
household heating and cooking; therefore, PM emis-
sions share many of the same sources as greenhouse-
gas emissions.
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MALARIA, DENGUE ENDEMIC
Malaria and dengue fever are endemic in many parts
of the world and, as described in the previous indica-
disease, with young children particularly vulnerable.
Suitability for transmission of mosquito-borne infec-
tious diseases is affected by factors including temper-
ature, humidity and precipitation.
For dengue, vectorial capacity, which expresses the
average daily rate of subsequent cases in a susceptible
population resulting from one infected case, is calcu-
lated using a formula including the vector to human
transmission probability per bite, the human infec-
tious period, the average vector biting rate, the extrin-
sic incubation period, and the daily survival period.
The second highest vectorial capacity for both den-
gue vectors were recorded in 2017, with the 2012–17
average 7·2 per cent and 9·8 per cent above baseline
for Aedes aegypti and Aedes albopictus, respectively.
This change emphasizes the continued upward trend
of climate suitability.
For malaria, the number of months suitable for
transmission of Plasmodium falciparum and P vivax
malaria parasites is calculated on the basis of tem-
perature, precipitation, and humidity. Furthermore,
climatic changes, including increasing temperature
and earlier snowmelt, contribute to hotter, drier con-
ditions, which increase the risk of wildfires.
Yet, wildfires remain an important component
of many ecosystems, although they can be ecologi-
cally harmful through human ignition or when forest
management practices do not fully account for peri-
odic, natural burning.
OTHER HEALTH ISSUES
Many of the trends identified in the 2019 Lancet
Countdown report are deeply concerning. Green-
house-gas emissions continue to rise. The most
immediate and direct impact of a changing global cli-
mate on human health is seen in the steady increase
in global average temperature, and the increased fre-
quency, intensity, and duration of extremes of heat.
The health threats include heat stress and heat
stroke, acute kidney injury, exacerbation of conges-
tive heart failure, and increased risk of interpersonal,
and collective violence. In particular, during periods
of extreme heat, young children have a greater risk of
electrolyte imbalance, fever, respiratory disease, and
kidney disease.
Also globally, crop yield potential for maize, win-
increases in temperature challenging efforts to
achieve SDG 2 to end hunger by 2030. The data sug-
gests that global yields of these four key crops are
reduced respectively by 6 per cent, 3·2 per cent, 7·4 per