Generalist species with high genetic diversity and rapid reproduction are likely to benefit from climate change. Many species that exhibit these characteristics are carriers of agricultural pests and diseases.
To be clear, not all species will suffer equally from climate change. Indeed, there are species that will be resilient and others that will even benefit from global warming.
The main beneficiaries are plants from the northern regions of Europe, Asia, and North America and, to a lesser extent, in southern South America and New Zealand. In these regions, plants will benefit from longer growing seasons (earlier springs and shorter winters) and higher CO2 concentrations (which will increase photosynthetic rates).
Closer to home, a variety of African species are also expected to benefit from climate change. These include generalist species currently limited by interactions with localized specialists that are—at least at present—better competitors for limited resources.
Some tropical species can thrive as their habitats become increasingly hot and humid. Species with high genetic diversity that reproduce rapidly (allowing rapid adaptation to environmental changes) are also likely to benefit.
Unfortunately, many species with these characteristics carry disease and are agricultural pests. For example, populations of coffee borers (Hypothenemus hampei), the most notorious African coffee pest, are expected to increase significantly in a warmer world. This growing threat is of particular concern given that higher temperatures have already reduced coffee collected in countries like Tanzania up to 50%.
One group of currently threatened species that could benefit from a warmer world are sea turtles. Researchers working in Cape Verde speculate that the island nation’s loggerhead sea turtle (Caretta caretta VU) populations will benefit from the growing female sex ratio (as expected in warmer conditions) as a single male can breed with multiple females.
However, the researchers note that this population requires continued monitoring as insurance against demographic stochasticity which could become a greater threat due to climate change. With unprecedented climate change looming, mosquito-borne diseases, including malaria and dengue fever, will have a new and unpredictable impact on humans and wildlife.
Although climate change is global in nature, changes due to habitat alteration occur more quickly at the local scale and have significant effects on mosquito-borne diseases. For example, the destruction of the Peruvian rainforests resulted in more than 120,000 cases of malaria at the end of the 1990s, against less than 150 nine years earlier.
Many species that exhibit these characteristics are carriers of agricultural pests and diseases. The Congo Basin rainforests are home to around 20% of all known plant and animal species on Earth. However, habitat modification continues at an alarming rate.
These threats are exacerbated by the fact that Africa, and in particular Central Africa, are expected to be among the hardest hit by climate change. Projected temperature increases would lead to longer malaria transmission seasons and a 5-7% extension.
Combined with projected population growth, climate change would nearly double the number of people at risk of dengue infection by 2080. This is worrying because Africa is particularly vulnerable to environmental change due to its limited adaptive capacity, widespread poverty, and low levels of development.
How, then, will habitat alteration and climate change affect mosquito-borne diseases such as malaria? The relationship between disease transmission, habitat modification, and climate change is complex. Although deforestation increases the risk of disease transmission, different malaria carrying mosquitoes (Anopheles spp.) are adapted to different microclimates.I
ronically, our multi-faceted ecosystems both play the role of maintaining cycles of transmission with cross-infection to humans, and regulating those cycles while controlling spill-over into human populations. The balance between these factors is influenced by the availability of suitable habitats for mosquitoes and reservoir hosts of infection.
In an ideal world, transmission cycles are regulated by density-dependent processes such as acquired immunity to infectious diseases and limit the carrying capacity of the environment to support insects and hosts. Altered natural habitats and possible increases in disease transmission from animals to people also increase the potential risks of new pathogens adapting to human hosts.
Only about 2,000 of the approximately 1 million unique viruses carried by wild vertebrate species with potential zoonotic threats have been described. For example, when a chimpanzee lentivirus was first released to humans in the 1930s, few people died.
But the disease took hold in the fast-growing African city of Kinshasa in the Democratic Republic of Congo and evolved into a form that effectively attacks humans. More than 78 million people were infected between 1981 and 2015. To date, the disease it causes, AIDS, has killed more than 39 million people, while an estimated 37 million more are living with HIV.
Today, habitat modification, such as deforestation, not only drives species to extinction and emits a lot of climate-altering carbon dioxide, but it also increases the chances of mosquito-borne diseases, such as malaria and dengue fever, infecting more humans in new places. Technological advances, including mathematical and computer modeling, genomics, and satellite tracking, will hopefully allow us to predict future disease outbreaks better. But we can also reduce epidemic opportunities by taking better care of our environment.