I have done and share some research about the potential
effects of climate change in vector-borne illnesses such as malaria, a
biological agent, and some possible ways to overcome this problem, but what
about another kind of threat: heat.
Heat stress is mentioned in the Atlas of Health and
Climate as a danger for human life. It “occurs when the body’s
means of controlling its internal temperature starts to fail”.
The body controls the internal temperature by sweating;
blood transports the heat from the inside to the surface (skin) and by evaporation
(sweating) it is liberated; that is why in hot days it feels hotter and more
uncomfortable in places with high humidity.
As heat stress is more dangerous in urban area (Argüeso) than
in rural ones and as it is affected by climate change I have decided to
explicitly mention the symptoms indicated in HSE (UK):
·
an inability to concentrate
· -
muscle cramps
· -
heat rash
· -
severe thirst - a late symptom of heat stress
· -
fainting
· -
heat exhaustion - fatigue, giddiness, nausea,
headache, moist skin
· -
heat stroke - hot dry skin, confusion,
convulsions and eventual loss of consciousness. This is the most severe
disorder and can result in death if not detected at an early stage
A study made in China by Ma, shows that heat
waves have significantly (5%) increased mortality. The effects depend on
variables as age, gender, population density, region inside the country; meaning
the mitigation/adaptation measures should be developed at local level.
Note
1: This conclusion could mean that it would be necessary to make a study
city by city (if not neighbour by neighbour) to define the correct adaptation measures
to heat, including among other topics: hospital and schools infrastructure, public
transportation, working hours and so on. This would mean funds. I presume the
lower the funds, the coarse the evaluation and I probably less effective
actions.
In another study Oleson
says that heat stress is the main cause of mortality among humans related to
weather.
But, how we quantify/evaluate a heat-wave
(heat-shock, heat-stress)? In 2006 Epstein
had already discussed this topic explaining that the assessment of thermal stress
and its “translation” to physiological and psychological tension is not easy. There
are a number of variables to take into consideration and some of them are not simple
to measure or obtain.
Later, in 2015 Freitas
again review the topic mentioning 162 thermal indices and Havenith
explains the the uses of these indices and modelling have helped to reduce
mortality and morbidity in a number of fields as military, sports and other.
Note
2: With a proper assessment of the heat-stress it would be possible to
take measures and do the proper design and adaptation of clothing, houses, stores,
factories, hospitals, schools and others like public transportation and hospitals
infrastructure for keeping people safe. In case you want to know in the case of
Ma already mentioned
“Heat waves were defined as ≥2
consecutive days with mean temperature ≥95th percentile of the year-round
community-specific distribution”.
In 2012 Coumou
et al. mentioned a number of catastrophic events around the world from 2000
to 2011, some of them very expensive other producing a high number of
casualties, and they said that there is
strong evidence that those relates to extreme temperature and rain are related with
“human influence on climate”.
Note
3: Financial Consequences: This
blog is mainly about the effects of the changes in the climate on people´s
health, but I would like to emphasize that health is not the only issue
associated with heat. There are some literature (Epstein,
Dunne)
linking this issue with productivity and labour; i.e. an economic aspects that
would be affected. Maybe this topic could be the real force making some
countries and people to understand that the change is for real and it is not going
to be for free for anyone.
