EDITORIAL The average global temperatures on our planet are increasing due to
rising anthropogenic greenhouse gases in the atmosphere, in particular
carbon dioxide (CO2).1,2 There is an
urgent need to call for action on global warming, which is resulting in
extreme weather and related catastrophes.1 ,2 The
Earth’s rising temperature is evidenced by warming of the oceans,
melting glaciers, rising sea levels, and the diminished snow cover in
the Northern Hemisphere. Climate-related factors can affect
interactive atmospheric components (chemical and biological) and their
interrelationship with human health.
Climate change, a physics and meteorological event that affects health
in the whole biosphere started to receive attention around the
mid-twentieth century. Air pollution is the driving force of the Earth’s
warming powered by the greenhouse effect (Figure 1). Environmental
changes are occurring in frequency, intensity, type of precipitation,
and extreme weather events, such as heatwaves, droughts, floods,
blizzards, thunderstorms, sandstorms, and hurricanes. These are real and
daunting challenges for the human and biosphere health, impacting the
food and water supplies.1 ,2 Urbanization, with its
high level of vehicle emissions and westernized lifestyle, is linked to
the rising levels of particulate matter in the air, food supplies, soil,
freshwater, and oceans. These environmental changes are correlated with
the increased frequency of respiratory allergic diseases and bronchial
asthma observed over recent decades in most industrialized countries and
is continuously rising in developing countries.1-5
This issue of Allergy focuses on the interrelationship between
climate change, air pollution and human health.3-7Climate change is an important medical aspect in allergology as we are
observing an increasing incidence of allergic diseases indirectly
related to rising temperatures and are becoming a high socio-economic
burden.1-3,8 Allergies and asthma appear to be at the
front line of the sequelae of climate change along with infectious and
cardiovascular diseases.1,5
Cecchi et al. focus on the development and exacerbation of allergic
diseases can be explained in terms of the exposome, a concept that
includes all the environmental exposures from conception onwards.
Multiple factors can trigger a pollen-induced respiratory allergy, such
as airborne endotoxin levels and microbial composition of pollen, and
these comprise a “pollen exposome”.4,9
Susan Prescott has written an editorial in this issue bringing the
attention to climate change and bidiversity aspects. At the time of Neil
Armstrong’s lunar landing 50 years ago, Prof. Rene Dubos, a renowned
microbiologist, delivered the seminal lecture “The Spaceship Earth”.
He was ahead of his time and warned of an “altered immunity” driven by
environmental problems and loss of biodiversity. Most of his predictions
proved correct and we are now understanding at a molecular level the
pathophysiological mechanisms involved in allergic
diseases.8
Climate change indirectly affects allergies by altering the pollen
concentrations, allergenic potential, composition, migration of species
and growth of new ones. Air pollution and climate change have resulted
in the faster growth of allergenic plants, increasing the aeroallergen
load for patients with inhalant allergy. Phenological studies indicate
longer pollen seasons and emerge earlier in the
year.1,4,5,8 Pollen and mold allergies are generally
used to evaluate the interrelationship between air pollution and
allergic respiratory diseases, such as rhinitis and asthma. Studies show
that plants exhibit enhanced photosynthesis and reproductive effects and
produce more pollen as a response to high atmospheric levels of
CO2. 1,4,8 Pollen allergens have been
demonstrated to trigger the release of pro-inflammatory and
immunomodulatory mediators that accelerate the onset of allergy and the
IgE-mediated sensitization. Lightning storms or wet conditions rupture
the pollen grains releasing the allergenic proteins that cause asthma
exacerbations in patients with pollinosis
(thunderstorm-asthma).1,3,4,7,10 As a result of
climate change, patients with seasonal allergic rhinoconjunctivitis and
asthma have more intense symptoms and need stronger
medication.1,4,8 In addition to respiratory illnesses,
Fairweather et al. demonstrate the effect of environmental changes on
cardiovascular, brain and mind, gastrointestinal, skin, immunologic and
metabolic effects.1,3,4,7 The migration of stinging
and biting insects to cooler climates has caused an increase in insect
allergies in those areas.
Prunicki et al. focus on the contribution of wildfires and deforestation
and their contribution to global warming and immunological effects. It
should be noted that in the last fifty years, half of the pluvial
forests on Earth have been lost. Deforestation and forestation
degradation is estimated to occur at a rate of 13 million hectares per
year, mostly for agricultural purposes. Wildfires are becoming
increasingly frequent, posing a serious risk to human health. The fine
particulate matter (PM2.5) in wildfire smoke exacerbates
asthma attacks, among other health problems. A study of 67 subjects
demonstrated that those exposed to wildfire smoke had significantly
higher levels of C-reactive protein and IL-1β compared with
controls.6 The elevated levels of these two biomarkers
are indicative of airway inflammation.
Global warming and climate change need actions throughout the whole
world with joined forces of all capabilities. These efforts are
sometimes hampered by the unresponsiveness of governmental institutions
and the general population, the lack of infrastructure and poverty. An
action plan is needed to disseminate information on health-related
problems associated with climate change. Patients with pollen allergies
or asthma should be educated on the higher health risk during a
thunderstorm or pollen season and the need for appropriate medication if
staying outdoors. In collaboration with environmental organizations,
physicians should take the lead to promote actions to mitigate air
pollution and advocate the need to reduce global warming to protect our
health.