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Perspective
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Christoph Eberle

As Climate Changes, So Does our Health

What challenges rising temperatures bring in the future. The latest in our Climate and Pharma series.

Some claim climate has always been changing; but what is our contribution? How irreversible is our impact, and how hostile to life? The basics of climate change are measurable and explained by physical sciences. Natural and anthropogenic gases have been identified and classified with regards to their relative contribution to global warming. These gases enhance the natural greenhouse effect that exacerbates climate change. Current research aims to understand to what extent this occurs due to natural carbon cycles and what has been accelerated by human intervention. What consequences to draw from this body of data and how actionable these scientific observations ought to be in the political sphere helped countries reach a consensus for the 2015 Paris climate accord.

How climate change may affect immune health

“Was alle angeht, können nur alle lösen. – What affects everybody can only be solved by everybody”, as Dürrenmatt appended to his play "The Physicists" in 1961, conceived during Cold War fears of nuclear weapons and arms race. Though his admonition remains valid, we regrettably find true in our time also: what affects everybody, must be acknowledged by everybody. Assessing man-made change to climate patterns remains controversial in public opinion, despite increasing weather extremes undermining human livelihood. Irrespective of what prediction models tell: how may general wellbeing, particularly our immune health, need to adapt to a climate shifting to higher average temperatures in decades to come?

It is expected that infectious diseases will spread. Warmer oceans support the survival of V. cholerae inhabiting phytoplankton. Algal blooms containing toxic concentrations of this bacterium can wash ashore and contaminate drinking water. Through infected marine organisms the bacterium enters the food chain. Both paths of infection lead to rapid cholera outbreaks in communities close to the sea. Various mental disorders have been associated with stress, anxieties and traumata during and because of natural disasters such as hurricanes, floods, famine and drought. Due to potentially colder winters and hotter summers, prevalence of allergies may change due to prolonged pollen seasons. Air pollution particularly in urban areas has reached levels that not only lead to higher susceptibility to respiratory complications – both acute and chronic – but harm maternal and child health.

With known diseases resurging or accelerating, new illnesses emerge in areas, where surface mean temperatures permanently increase. This facilitates heat stress leading to more cardiovascular diseases, including strokes, angina, heart attacks along with complications stemming from hypertension and dehydration. Furthermore, vector-borne diseases can spread into geographical regions in which blood-feeding insects could not survive before. Mosquitos, ticks and fleas grow faster in warmer conditions. They are among the carriers, mostly transmitting viral infections, predominantly caused by RNA viruses. Malaria falls as prominent example in this category of zoonoses, but in recent years more endemic incidents of dengue, Zika, chikungunya, Lyme disease or eastern equine encephalitis (EEE) have been documented.

According to World Health Organization (WHO) statistics vector-borne diseases currently make up 17% of all infectious diseases. Though many are preventable, their potentially higher prevalence presents challenges to drug developers due to an already existing gap in current options for antiviral treatments. These challenges are complicated by growing pathogen resistance to evade antiviral medicines developing in the environment. As healthcare providers are likely to encounter known and unknown symptoms with all these disease patterns requiring therapeutic intervention, there will be greater need for services to patients seeking medical attention. Consequently, the demand for commercially available pharmaceuticals and for the release of new ones will rise. Adapting to these changed prevalence rates will challenge health care systems in the future.
 
An additional, if not key contributor to disease emergence in turn may be disturbing habitats through human development. It comes along with overpopulation and has exhibited a danger to the planet’s natural resources. On a global scale industrialization and urbanization increasingly erode ecosystem sustainability. Anthropogenic activities drive these processes mainly due to an expansion of the production of consumer goods, transportation, travel, agriculture and energy use. How these factors affect each other, is yet poorly realized. Clearly, ecological sustainability and human health need to be generally perceived as reciprocal. It will be necessary for policy makers to prioritize the protection of both equally. Realizing this goal is justified considering combined costs and effects on societies. Much will depend on gaining international media attention to promote local mitigation and adaption projects and to raise public health hazards arising from human-made climate change. Even if its impacts can be attenuated, they may induce further geo processes, which current models cannot predict.

Complex problem, complex solution?

As with every science, there are uncertainties; it is best these are resolved by progress of the research field producing them. Yet the statements of climate science point to the future and therefore in part remain up for debate. Its dilemma is to become obsolete, if we cannot counteract the consequences of global warming, while waiting to see the same predictions come true as proof to convince sceptics. For resolution neither ideology nor sensationalism qualify. Complex issues such as this require collaboration from all societies, spearheaded best by science diplomacy. When the U.S. re-enters the Paris climate accord in 2021, it reaffirms the persuasive power of example; most important are the ones we follow. On these matters, on any matter the best was civic participation can turn into is when everyone makes it their own what concerns everyone.

At the beginning of the 21 points accompanying his play "The Physicists" Dürrenmatt proclaims: “Eine Geschichte ist dann zu Ende gedacht, wenn sie ihre schlimmstmögliche Wendung genommen hat. –  A story has been thought out to its conclusion when it has taken its worst possible turn.” Needs did and will drive our transformation of the global habitat. Now for the first time since we set out to “subdue the earth” we reckon that we do not know this story’s end; while writing it, we must hope it shall not take its worst turn.

You can find other stories in our climate series here.

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