In an effort to document and understand the impacts of climate change, researchers have largely focused on aspects that influence quality of life for people. This impact is well-documented and important, but only touches the surface of changes affecting the planet. There are various lines of evidence - both direct and indirect - that show climate change is also behind other dramatic transformations of the planet, including species range shifts, species extinctions, overall biodiversity decline, ecosystem services collapse, and infectious disease expansion. As climate changes,
species must either tolerate the change, move, adapt, or face extinction. An estimated 8% of all species are project to go extinct due to their inability to make these changes quickly enough (Urban 2015). This does not take into account the myriad other ways that humans are currently impacting species and their habitat.
species must either tolerate the change, move, adapt, or face extinction. An estimated 8% of all species are project to go extinct due to their inability to make these changes quickly enough (Urban 2015). This does not take into account the myriad other ways that humans are currently impacting species and their habitat.
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Modified Species Ranges
Scientists have long assumed that species would shift their range as climate conditions advanced, including by shifting their ranges in latitude and elevation (Elsen et al. 2015). However, the speed at which these changes have occurred is unexpected. Of more than 4,000 species sampled from around the world, roughly half are on the move. The ones on land are moving an average of more than 10 miles per decade, while marine species are moving four times faster. Some individual species are moving far more quickly. Atlantic cod and Europe's purple emperor butterfly moved more than 125 miles in a single decade (Welch 2017).
There's broad evidence that alpine communities are being transformed. Plant species are responding by moving further up mountains. Climate change is considered particularly problematic for these montane species because they show high rates of local endemism and often inhabit narrow elevational ranges. Local endemics are particularly at risk, because they are unlikely to have populations in areas of suitable habitat after a range shift. Also, species moving into new habitats could result in hybridization, where plant populations are being threatened as a consequence of genetic swamping and outbreeding depression. Left with nowhere else to go, montane species are predicted to become increasingly susceptible to the stochastic extinctions typical of small or declining populations (Elsen et al. 2015).
Animals that breed more slowly, including primates, elephants, and marsupials, which evolved in stable tropical climates, are less likely to adapt to quickly changing environment. The relative stability of their environment means they are more vulnerable to extreme temperatures and storms.
Habitat fragmentation is likely to impede the ability of species to move with the rapidly changing climates that we are likely to experience in the future. At the same time, loss of or degradation of important habitats and microhabitats will require species to move to new, more suitable locations or to somehow adapt to change at their current locations.
The New York Times has a pretty spectacular article on this very topic, "Why our future may depend on the fate of birds."
Spread of Infectious Diseases
Malaria now appears higher up mountain slopes in Colombia and Ethiopia, as rising thermostats make way for mosquitoes at higher elevations. Leishmaniasis, a sometimes-fatal, once primarily tropical affliction, has moved into northern Texas as the sandflies that host the disease-causing parasite head north. Agriculture is feeling the effects too, as crop pests expand their range. Diamondback moths, which ravage the cabbages, kale, and cauliflower grown by poor urban farmers, are spreading in South Africa. In Latin America, coffee plant fungi and pests are appearing in new areas. The same is happening to French olives, wine grapes, and lavender (Welch 2017).
Similarly, native forest birds on the Hawaiian island of Kauai are rapidly dying off and facing the threat of extinction as climate change heats up their habitat and allows mosquito-borne diseases to thrive. Higher temperatures caused by global warming increase the spread of diseases such as avian malaria in wooded areas once cool enough to keep them under control. Most of Hawaii’s forest birds are restricted to forests in high elevations where disease has been seasonal or absent. A sharp increase in disease has occurred over the last 15-years in the upper-elevation forests of Kauai’s Alakai Plateau.
Phenology
Warming is also shifting the timing of biological cycles. Globally, frogs and other amphibians are breeding an average of eight days earlier with each passing decade, while birds and butterflies are reproducing four days earlier (Welch 2017). Species are threatened by the unraveling of ecological relationships. Take for example the red knot, a shorebird that migrates from the tropics to the Arctic each spring to breed and feed on insects. Because Arctic snows are now melting and insects are hatching weeks before the birds arrive, there’s too little food for the red knot chicks—and at least in the case of the population that migrates back to West Africa, the young birds’ beaks are too small to pluck mollusks from sandy beaches.
In West Greenland, the mortality of young caribou is rising because the plants that mothers eat in calving season are no longer abundant enough. In Japan, the herb Cordyalis ambigua is now flowering before bumblebees emerge to pollinate it, and as a result it’s producing fewer seeds. Meanwhile, bumblebees globally are being pushed out of the southern part of their range by rising temperatures, and for whatever reason are not expanding their range much in the north (Welch 2017).
Environmental cues trigger the onset of egg laying changes which are asynchronous (or not timed correctly) to the environmental conditions prevailing when chicks are reared and when birds' energetic demands are the highest. Differential climate change between summer and winter ranges may also lead to problems in the transition for migratory birds.
Disappearing Habitat
If water temperatures stay higher than usual for many weeks, zooxanthellae - a symbiotic dinoflagellate which are planktonic - that corals depend on for some of their food, leave their tissue. Without zooxanthellae, corals turn white because zooxanthellae give corals their color. Coupled with this, much of the elevated carbon dioxide levels in the atmosphere are absorbed by oceans. pH levels drop and oceans become more acidic. This results in a decrease in calcium carbonate absorption by corals which they need to build skeletons. Coral bleaching is the principal threat to the 2nd largest living structure on Earth – the Great Barrier reef. And as a result of wasting reef systems, it has profound impacts on all the other species dependent upon it, including vast assemblages of clams, fish, and sea urchins. For example, in the great barrier alone, 1500 species of fish are dependent on the structures and ecocystem that is a product of these corals. Recent evidence suggests many of these fish are moving from reefs that have been bleached to other unaffected reefs, changing the dynamics and community structure.
Collapse of Pollination Services
Bees, in particular, are facing the danger of a phenomenon called colony collapse disorder (CCD). “CCD most likely stems from a combination of problems associated with agricultural beekeeping, including pathogens, nutritional deficiencies and lack of a varied diet, exposure to neonicotinoid insecticides and other pesticides, lack of genetic diversity, habitat loss, and transportation stress. Pesticides, stress, and lack of diversity can actually exacerbate the vulnerability of bees to pathogens (Young 2015).”
So what's the solution? New research by the Environmental Protection Agency shows that “the cost of inaction is really high, and [the cost of] reducing emissions pales in comparison. We can take aggressive actions now including cutting emissions of carbon dioxide and other greenhouse gases, and proactively adapting to a warming world, which would prevent a lot of the damage, reducing the annual economic toll in some sectors by more than half" (From ruined bridges to dirty air, EPA scientists price out the cost of climate change). Individual actions include reducing your carbon footprint, and aligning protection of the environment with the market economy.
Biodiversity Loss and Climate Change
Biodiversity loss and global climate change are interconnected and often exacerbate each other. Biodiverse ecosystems tend to be more resilient to environmental changes, including climate change. The presence of a variety of species within an ecosystem provides redundancy and can help maintain ecosystem functions, even when some species are affected by changing conditions. Biodiverse ecosystems, especially forests and wetlands, also play a crucial role in sequestering carbon dioxide from the atmosphere. Trees, plants, and soil organisms capture and store carbon, helping mitigate climate change by reducing greenhouse gas concentrations.
Alternatively, climate change can lead to feedback loops that negatively impact biodiversity. For example, rising temperatures, extreme weather events, and altered precipitation patterns can disrupt ecosystems, making them less suitable for certain species. This, in turn, can lead to further biodiversity loss (Widerberg et al. 2022).
Scientists have long assumed that species would shift their range as climate conditions advanced, including by shifting their ranges in latitude and elevation (Elsen et al. 2015). However, the speed at which these changes have occurred is unexpected. Of more than 4,000 species sampled from around the world, roughly half are on the move. The ones on land are moving an average of more than 10 miles per decade, while marine species are moving four times faster. Some individual species are moving far more quickly. Atlantic cod and Europe's purple emperor butterfly moved more than 125 miles in a single decade (Welch 2017).
There's broad evidence that alpine communities are being transformed. Plant species are responding by moving further up mountains. Climate change is considered particularly problematic for these montane species because they show high rates of local endemism and often inhabit narrow elevational ranges. Local endemics are particularly at risk, because they are unlikely to have populations in areas of suitable habitat after a range shift. Also, species moving into new habitats could result in hybridization, where plant populations are being threatened as a consequence of genetic swamping and outbreeding depression. Left with nowhere else to go, montane species are predicted to become increasingly susceptible to the stochastic extinctions typical of small or declining populations (Elsen et al. 2015).
Animals that breed more slowly, including primates, elephants, and marsupials, which evolved in stable tropical climates, are less likely to adapt to quickly changing environment. The relative stability of their environment means they are more vulnerable to extreme temperatures and storms.
Habitat fragmentation is likely to impede the ability of species to move with the rapidly changing climates that we are likely to experience in the future. At the same time, loss of or degradation of important habitats and microhabitats will require species to move to new, more suitable locations or to somehow adapt to change at their current locations.
The New York Times has a pretty spectacular article on this very topic, "Why our future may depend on the fate of birds."
Spread of Infectious Diseases
Malaria now appears higher up mountain slopes in Colombia and Ethiopia, as rising thermostats make way for mosquitoes at higher elevations. Leishmaniasis, a sometimes-fatal, once primarily tropical affliction, has moved into northern Texas as the sandflies that host the disease-causing parasite head north. Agriculture is feeling the effects too, as crop pests expand their range. Diamondback moths, which ravage the cabbages, kale, and cauliflower grown by poor urban farmers, are spreading in South Africa. In Latin America, coffee plant fungi and pests are appearing in new areas. The same is happening to French olives, wine grapes, and lavender (Welch 2017).
Similarly, native forest birds on the Hawaiian island of Kauai are rapidly dying off and facing the threat of extinction as climate change heats up their habitat and allows mosquito-borne diseases to thrive. Higher temperatures caused by global warming increase the spread of diseases such as avian malaria in wooded areas once cool enough to keep them under control. Most of Hawaii’s forest birds are restricted to forests in high elevations where disease has been seasonal or absent. A sharp increase in disease has occurred over the last 15-years in the upper-elevation forests of Kauai’s Alakai Plateau.
Phenology
Warming is also shifting the timing of biological cycles. Globally, frogs and other amphibians are breeding an average of eight days earlier with each passing decade, while birds and butterflies are reproducing four days earlier (Welch 2017). Species are threatened by the unraveling of ecological relationships. Take for example the red knot, a shorebird that migrates from the tropics to the Arctic each spring to breed and feed on insects. Because Arctic snows are now melting and insects are hatching weeks before the birds arrive, there’s too little food for the red knot chicks—and at least in the case of the population that migrates back to West Africa, the young birds’ beaks are too small to pluck mollusks from sandy beaches.
In West Greenland, the mortality of young caribou is rising because the plants that mothers eat in calving season are no longer abundant enough. In Japan, the herb Cordyalis ambigua is now flowering before bumblebees emerge to pollinate it, and as a result it’s producing fewer seeds. Meanwhile, bumblebees globally are being pushed out of the southern part of their range by rising temperatures, and for whatever reason are not expanding their range much in the north (Welch 2017).
Environmental cues trigger the onset of egg laying changes which are asynchronous (or not timed correctly) to the environmental conditions prevailing when chicks are reared and when birds' energetic demands are the highest. Differential climate change between summer and winter ranges may also lead to problems in the transition for migratory birds.
Disappearing Habitat
If water temperatures stay higher than usual for many weeks, zooxanthellae - a symbiotic dinoflagellate which are planktonic - that corals depend on for some of their food, leave their tissue. Without zooxanthellae, corals turn white because zooxanthellae give corals their color. Coupled with this, much of the elevated carbon dioxide levels in the atmosphere are absorbed by oceans. pH levels drop and oceans become more acidic. This results in a decrease in calcium carbonate absorption by corals which they need to build skeletons. Coral bleaching is the principal threat to the 2nd largest living structure on Earth – the Great Barrier reef. And as a result of wasting reef systems, it has profound impacts on all the other species dependent upon it, including vast assemblages of clams, fish, and sea urchins. For example, in the great barrier alone, 1500 species of fish are dependent on the structures and ecocystem that is a product of these corals. Recent evidence suggests many of these fish are moving from reefs that have been bleached to other unaffected reefs, changing the dynamics and community structure.
Collapse of Pollination Services
Bees, in particular, are facing the danger of a phenomenon called colony collapse disorder (CCD). “CCD most likely stems from a combination of problems associated with agricultural beekeeping, including pathogens, nutritional deficiencies and lack of a varied diet, exposure to neonicotinoid insecticides and other pesticides, lack of genetic diversity, habitat loss, and transportation stress. Pesticides, stress, and lack of diversity can actually exacerbate the vulnerability of bees to pathogens (Young 2015).”
So what's the solution? New research by the Environmental Protection Agency shows that “the cost of inaction is really high, and [the cost of] reducing emissions pales in comparison. We can take aggressive actions now including cutting emissions of carbon dioxide and other greenhouse gases, and proactively adapting to a warming world, which would prevent a lot of the damage, reducing the annual economic toll in some sectors by more than half" (From ruined bridges to dirty air, EPA scientists price out the cost of climate change). Individual actions include reducing your carbon footprint, and aligning protection of the environment with the market economy.
Biodiversity Loss and Climate Change
Biodiversity loss and global climate change are interconnected and often exacerbate each other. Biodiverse ecosystems tend to be more resilient to environmental changes, including climate change. The presence of a variety of species within an ecosystem provides redundancy and can help maintain ecosystem functions, even when some species are affected by changing conditions. Biodiverse ecosystems, especially forests and wetlands, also play a crucial role in sequestering carbon dioxide from the atmosphere. Trees, plants, and soil organisms capture and store carbon, helping mitigate climate change by reducing greenhouse gas concentrations.
Alternatively, climate change can lead to feedback loops that negatively impact biodiversity. For example, rising temperatures, extreme weather events, and altered precipitation patterns can disrupt ecosystems, making them less suitable for certain species. This, in turn, can lead to further biodiversity loss (Widerberg et al. 2022).
Sources
Resources
- Elsen, P. R., & Tingley, M. W. (2015). Global mountain topography and the fate of montane species under climate change. Nature Climate Change, 5(8), 772.
- Pecl, G. T., Araújo, M. B., Bell, J. D., Blanchard, J., Bonebrake, T. C., Chen, I. C., ... & Falconi, L. (2017). Biodiversity redistribution under climate change: Impacts on ecosystems and human well-being. Science, 355(6332).
- Rosen J. (2019). From ruined bridges to dirty air, EPA scientists price out the cost of climate change. Los Angeles Times.
- Urban, M. C. (2015). Accelerating extinction risk from climate change. Science, 348(6234), 571-573.
- Welch 2017. Half of all species are on the move—and we're feeling it
- Widerberg, O., Boran, I., Chan, S., Deneault, A., Kok, M., Negacz, K., ... & Petersson, M. (2023). Finding synergies and trade‐offs when linking biodiversity and climate change through cooperative initiatives. Global Policy, 14(1), 157-161.
- Young, A., & Forest, H. A. E. (2015). Changes in phenology of flowering, correlation with climate variability, and response of honeybees.
Resources
- Climate change blamed for collapse of Hawaiian forest birds
- Ecosystems across Australia are collapsing under climate change
- The Staggering Worldwide Decline of Insects Is a Warning of Ecosystem Collapse
- Hughes, T. P., Kerry, J. T., Baird, A. H., Connolly, S. R., Dietzel, A., Eakin, C. M., ... & McWilliam, M. J. (2018). Global warming transforms coral reef assemblages. Nature, 556(7702), 492.
- Impacts of Climate Change on Wildlife
- How Climate Change has Affected Pollinators