Jun 16, 2020
In the last 130 years, the world has warmed by approximately 0.85oC. Most of the warming occurred in the past 35 years, with the five warmest years on record taking place since 2010.
This change is driven largely by human activities – particularly the burning of fossil fuels – increasing carbon dioxide and other human-made emissions into the atmosphere. 
These human made gases accumulating in the stratosphere are destroying the ozone layer.
“The main consequence of this stratospheric ozone depletion is reduced shielding of Earth’s surface against incoming solar UVR. This radiation is damaging to living organisms and hazardous to human health.”
IMPACT OF CLIMATE CHANGES ON HUMAN HEALTH
Climate change is already affecting population health worldwide, with risks increasing as the temperatures continue to rise. These risks are varied, including impacts related to extreme weather events, undernutrition, malaria and other vector-borne diseases, diarrheal and other waterborne diseases. Extreme weather and climate events are also a risk factor for noncommunicable diseases.
According to the World Health Organization, “Climatic conditions strongly affect water-borne diseases and diseases transmitted through insects, snails or other cold blooded animals. Changes in climate are likely to lengthen the transmission seasons of important vector-borne diseases and to alter their geographic range.“ 
Indeed climate change promotes the propagation of pathogens behind infectious diseases. In particular “changes in meteorological parameters substantially increase respiratory morbidity and mortality in adult patients with common chronic lung diseases, such as asthma and COPD, and other serious lung diseases”
It is also notable that the spread of diseases and apparition of places susceptible to epidemics encourage the migration of people to healthier places.
However “migration involves exposure to a new set of air pollutants and allergens, as well as changes in housing conditions, diet and accessibility to medical services, all of which are likely to affect migrants’ health. (…) Climate change is likely to modify the profile of several diseases, including respiratory diseases.”
Coronaviruses are a large family of viruses which may cause illness in animals or humans. In humans, several coronaviruses are known to cause respiratory infections ranging from the common cold to more severe diseases such as Middle East Respiratory Syndrome (MERS) and Severe Acute Respiratory Syndrome (SARS). The most recently discovered coronavirus causes coronavirus disease COVID-19.
rThis new virus and disease were unknown before the outbreak began in Wuhan, China, in December 2019 so people have a virgin immune system to fight against it. Even though the symptoms of flu and coronavirus are similar and the flu is known to be a winter disease, it is too early to be sore that the coronavirus is a winter virus. Moreover a few virology studies show that many viruses can survive despite an increase in temperature.
Nevertheless, it was reported that the lockdown due to COVID pandemic, positively reduced the emission of gaz and particles, leading to an improvement of air quality. However, some experts still warn that this effect was only temporary, and climate changes is still a long term concern.
NEW CHALLENGES TO EPIDEMIOLOGY
Governments face a tough challenge facing up to gas emissions and reducing the risks to human health and in particular decreasing the effects of environmental factors affecting respiratory diseases. Policies have been put in place to replace polluting sources of energy by non-polluting ones, but also to limit the use of fossil fuels and encourage the use of public transports.
Public awareness of the consequences of climate change on health is also increasing and people are encouraged to play their part.
Finally by increasing our knowledge face to this new epidemic profile, new immunization programs will be developed.
 Climate change and respiratory diseases. Gennaro D’Amato , Lorenzo Cecchi , Mariella D’Amato and Isabella Annesi-Maesano.