The Impact of Climate Change on Wildlife Migration

 

How Are Plants and Animals Responding to Climate Change?

Climate change is driving significant shifts in species distribution, range boundaries, migration patterns, and phenology, with wide-ranging consequences for biodiversity and human societies.

Human-driven environmental changes are altering ecosystems and affecting millions of plant and animal species. Since 1850, Earth’s temperature has risen by 1.3°C due to greenhouse gas emissions, intensifying climate-related effects such as drought, extreme heat, sea level rise, and wildfires.

Drought

In 2022 and 2023, nearly a quarter of the global population faced drought conditions, with 2023 marking the driest year for rivers in three decades. Projections indicate droughts will become more frequent and severe, affecting between 33% and 62% of global land area depending on emission levels.

Extreme Heat

The past decade has recorded the ten hottest years in history, with 2024 ranking as the warmest. Climate change contributed to 41 extra days of extreme heat that year, increasing ecosystem vulnerability, wildfire risks, hurricane intensity, and rising sea levels.

Climate change is reshaping ecosystems, altering species distribution, migration patterns, and seasonal behaviors. These shifts have profound implications for biodiversity and human societies.

Since 1850, human-driven greenhouse gas emissions have raised global temperatures by 1.3°C, intensifying extreme weather events such as droughts, heatwaves, rising sea levels, and wildfires.

Sea Level Rise

Global sea levels have risen by 8–9 inches (20.3–22.9 cm) since 1880, reaching a record high in 2023. Under the most optimistic scenario aligned with the Paris Climate Agreement (1.5°C warming), sea levels are expected to rise by 1 foot (30.5 cm) above 2000 levels by 2100. However, if current warming trends continue toward 3.1°C by 2100, sea levels could rise 6 feet or more, dramatically reshaping coastlines.

Wildfires

Wildfires are becoming more frequent, intense, and widespread. Between 2001 and 2023, the area burned increased by 5.4% annually, with 6 million more hectares burned per year than in 2001. The global fire season lengthened by 18.7% between 1979 and 2013, fueled by drier, hotter conditions. Modern wildfires also emit 50% more carbon per unit burned than those in the early 2000s, exacerbating climate change.

Human Impact on Ecosystems

Human activities are altering ecosystems in ways that reduce habitat availability, disrupt biodiversity, and accelerate climate change.

• Deforestation & Land Conversion: Over 18 million acres of forest are lost annually due to agriculture and development.
• Freshwater Loss: Global water demand has contributed to a 30% decline in freshwater ecosystems, endangering species that rely on rivers, lakes, and wetlands.
• Pesticide Use: Agricultural pesticides, totaling 3 billion kilograms annually, pose significant risks to ecosystems. A 2022 study found pesticide exposure on 33% of U.S. agricultural land reached hazardous levels.

Observed Changes in Plants and Animals

Species Distribution & Migration

Land-based species are shifting toward higher latitudes and altitudes to escape rising temperatures. In the oceans, melting polar ice has allowed marine species to expand into new regions, disrupting ecosystems.

For example, Adélie penguins, which depend on stable sea ice, have experienced a 40% population decline in eastern Antarctica due to habitat loss and increased travel distances for food and breeding.

Coral Bleaching

Ocean warming and acidification are causing coral reefs to expel their symbiotic algae, a process known as coral bleaching. Since 2009, coral reefs have declined by 14%, and a 2024 analysis found that 44% of the remaining 892 warm-water coral reef species are at risk of extinction. Given that coral reefs support 25% of marine species, their loss threatens entire marine ecosystems.

Phenological Shifts

Climate change is altering seasonal biological events, known as phenology. Rising temperatures have triggered earlier flowering and insect emergence, disrupting ecological interactions.

• A 2022 study found that the first flowering dates of 406 plant species shifted an average of 26 days earlier since 1986.
• This misalignment threatens pollination, which is essential for 35% of global food crops.
• Bee populations, already declining due to habitat loss and pesticide exposure, face increased risks from climate-driven changes in plant flowering cycles.

Range Expansion and Population Growth

Rising global temperatures are creating favorable conditions for disease-carrying insects, posing a significant public health threat worldwide.

In the U.S., ticks are responsible for 95% of all vector-borne diseases, including Lyme disease and Rocky Mountain spotted fever. Historically, their range was confined to the Northeast, Gulf Coast, and Upper Midwest. However, climate change has enabled their expansion into the western U.S. and southern Canada. Lyme disease, the most common vector-borne illness in the country, has seen a nearly 25-fold increase in annual reported cases since 1982.

Similarly, warming temperatures are accelerating the spread of mosquitoes—widely regarded as the deadliest creature on Earth. Mosquito-borne diseases cause over one million deaths and 700 million infections globally each year. Warmer conditions speed up mosquito development and extend the disease transmission season by a month or more. Additionally, the increased frequency and intensity of extreme precipitation since the 1950s have led to more standing water, providing ideal breeding grounds for mosquitoes.

Supporting Species Adaptation to Climate Change

Human-induced greenhouse gas emissions have set in motion long-term changes to ecosystems and wildlife. According to the International Union for Conservation of Nature (IUCN), climate change is already affecting at least 10,967 species on its Red List of Threatened Species. Without intervention, Earth is on track for a 3.1°C temperature rise, which could drive one-third of all species to extinction by the end of the century.

Two key conservation strategies—assisted migration and protected areas—are being employed to help species adapt.

Assisted Migration

Assisted migration involves relocating plant and animal species to more suitable habitats. Recognizing the urgency of climate-driven threats, the U.S. Endangered Species Act was updated in 2023 to permit this practice, which was previously restricted due to concerns about potential ecological disruption. However, climate change is progressing at a pace that exceeds many species' natural ability to adapt.

For example, the U.S. Forest Service is testing assisted migration in Minnesota by introducing tree species that are resistant to the emerald ash borer, a non-native insect that decimated local ash tree populations. Similarly, wildlife officials in Florida are considering relocating key deer—native to the Florida Keys—to the mainland to protect them from habitat loss due to rising sea levels and saltwater intrusion. With only 1,000 individuals remaining, relocation may be their last chance for survival.

Protected Areas

Protected areas have long served as a cornerstone of biodiversity conservation, safeguarding ecosystems from human interference. Globally, there are approximately 130,000 protected areas covering 13% of terrestrial surfaces and 6% of marine environments. In 2022, the UN Convention on Biological Diversity set an ambitious goal: to protect at least 30% of the world’s land, freshwater, and ocean areas by 2030.

Studies show that well-managed protected areas help reduce habitat destruction, preserve biodiversity, and improve species conservation outcomes compared to unprotected regions. Additionally, forests within protected areas release significantly fewer carbon emissions than those subject to deforestation and land clearing, further contributing to climate mitigation efforts.

By implementing these conservation strategies, humanity can play a critical role in supporting species adaptation and reducing biodiversity loss in an era of rapid environmental change.