The diseases that climate change intensifies represent a growing challenge for global public health.
This is indicated by a recent international study published in the journal Proceedings of the National Academy of Sciences (PNAS).
It analyzed how temperature, humidity, and precipitation influence the emergence and spread of 53 zoonotic diseases, that is, diseases transmitted from animals to humans.
The research, led by scientists from the Natural History Museum in London, included information from 65 countries and examined pathologies such as:
- hantavirus;
- rabies;
- plague;
- anthrax;
- West Nile virus, and;
- Ebola
Climate change as an accelerator of disease transmission
According to the study, climate change does not activate all diseases equally. Apparently, heat acts as a potent fuel for infections.
Thus, scenarios where warming amplified the threat were almost twice as frequent as those where it reduced it.
This trend is mainly driven by vectors such as mosquitoes and ticks.
In 69% of the cases where the link between thermal records and these pathogens was examined, scientists found a significant statistical connection.
On the other hand, rain and humidity behave more unpredictably in terms of disease transmission due to climate change.
These variables sometimes trigger infections and at other times halt them, depending on whether the carrier is an insect, a rodent, or livestock.
Specific cases of transmission
The study documented specific examples of how climate alters the risk of infection:
- Leptospirosis in Brazil: a 20-millimeter anomaly in weekly rainfall increased the risk of infection by 12%
- West Nile Virus (U.S. and Russia): annual thermal increase resulted in greater risk due to accelerated survival of mosquitoes
- Plague: initial warming triggers rodent populations, but excessive heat blocks the pathogen’s transmission
“Climate change is a global process that will affect almost all living beings on the planet. It is truly surprising that there is no consistent way to examine how this process affects different animals and the diseases they transmit,” stated David W. Redding, co-author of the work.
How the study analyzing the impact of climate change on diseases was conducted
The team reviewed more than 14,000 academic titles to filter the most robust 218 empirical studies.
This tracking allowed the collection of 852 individual statistical measurements from 65 countries.
Only works that demonstrated with concrete numbers how temperature, rain, or humidity alter real danger indicators were accepted.
The projections estimate that 97% of the analyzed locations where diseases caused by animals sensitive to temperature are reported will exceed increases of 1.5°C in annual average between 2041 and 2070.
However, the study exposed a blind spot: most works used simple statistical models to measure complex biological phenomena.
In reality, only 13% of the studies explored non-linear relationships.
Therefore, the researchers proposed developing models that understand the specific biology of each animal and creating a unified global surveillance network.
The call aims to design alert and control systems that allow for proactive action against the risks of global warming in public health.
