Nature on the move: How climate change is reshaping plants and wildlife worldwide

Climate change is already reshaping the living world. Plants are flowering earlier, forests are shifting uphill, animals are moving toward cooler regions, and entire food webs are being rearranged. Weather extremes add another layer of pressure: heatwaves, droughts, floods, wildfires and marine heatwaves can transform ecosystems in a matter of days or weeks.

Vegetation is moving with the climate

The clearest global signal is a geographical shift. As temperatures rise, many plant species are moving toward higher latitudes and higher elevations. The IPCC reports that among thousands of studied terrestrial, freshwater and marine species, roughly half to two-thirds have shifted their ranges in the direction expected from warming.

In mountain regions, this often means shrubs and trees moving upslope into areas that were previously too cold. At high elevations, however, there is a limit: species already living near mountain summits can eventually run out of space.

Spring is starting earlier

Warming is changing the seasonal calendar of nature. The IPCC finds that roughly two-thirds of observed spring biological events have shifted earlier. Bud burst, flowering, insect emergence, frog spawning, bird nesting and migration are all being affected.

This sounds simple, but ecosystems depend on timing. If plants flower before their pollinators are active, or if caterpillars peak before migratory birds arrive to feed their chicks, the mismatch can reduce food availability and reproductive success.

Forests face heat, drought and fire at the same time

Forests are being affected not only by gradually rising temperatures but also by more frequent extremes. Severe drought reduces tree growth and weakens trees, making them more vulnerable to pests and disease. Heatwaves can directly cause mortality. In some regions, warmer conditions also lengthen the season in which bark beetles and other insects can reproduce.

Wildfire adds a second shock. After repeated fires, some forests may fail to recover in their previous form and can shift toward shrubland or grassland. The IPCC has documented climate-linked increases in burned area and mass mortality events in vegetation.

Animals are also changing where they live

Wildlife is following temperature and habitat. Cold-adapted animals are generally retreating poleward or uphill, while warm-adapted species expand into new areas. This process is already changing the composition of ecological communities.

In some cases, new species can arrive faster than native species can adapt. That can increase competition, bring new predators or diseases, and create opportunities for invasive species.

Migration and breeding seasons are shifting

Birds, insects, fish and mammals often depend on seasonal cues. Climate change can alter the timing of migration, breeding, hibernation and spawning. The European Environment Agency notes that many seasonal events now occur earlier, including bird nesting, frog spawning and the arrival of migratory species.

The problem is not simply that everything happens earlier. Different species respond at different speeds. A predator may arrive too late for the peak of its prey, or a pollinator may emerge after flowering has already passed.

Oceans are changing even faster in some regions

Marine ecosystems are undergoing major shifts. According to the IPCC, many marine species have moved poleward as the oceans warm, with average range shifts measured at roughly 59 kilometres per decade across studied marine taxa.

Marine heatwaves are especially damaging because they can last for weeks or months. They have caused mass mortality in coral reefs, kelp forests, seagrass meadows, fish and seabirds. Coral bleaching is one of the clearest examples: prolonged heat forces corals to lose the algae they depend on, weakening or killing entire reef systems.

Changing oceans mean changing fisheries

Fish populations are moving as temperatures change. Species that once supported local fisheries may become less common, while warmer-water species appear in new regions. This is already affecting fishing communities, management boundaries and marine food webs.

At the same time, ocean acidification and declining oxygen levels create additional stress, especially for shell-forming organisms and species already near their physiological limits.

Deserts can expand – but the story is not uniform

Hotter and drier conditions can reduce vegetation cover in already dry regions, especially where drought becomes more frequent or rainfall becomes less reliable. But climate change does not produce the same effect everywhere. Some regions may receive more rainfall, while others become drier. Land use, grazing pressure and soil degradation can amplify or counteract climate effects.

Arctic and mountain ecosystems are among the fastest-changing

The Arctic is warming far faster than the global average. Shrubs are expanding northward, permafrost is thawing and sea ice is shrinking. Species such as polar bears, seals and Arctic seabirds are affected because their habitat and food chains depend on sea ice.

Mountain ecosystems face a similar squeeze. As temperatures rise, lower-elevation species move uphill and compete with cold-adapted species for limited space. Once the summit is reached, there is nowhere colder to move.

Extreme weather can change ecosystems suddenly

Long-term warming is only one part of the story. A single extreme event can have enormous ecological consequences. Heatwaves can cause mass mortality. Drought can kill trees across entire landscapes. Floods can reshape rivers and wetlands. Cyclones can destroy forests and coastal habitats. Marine heatwaves can wipe out kelp forests or trigger coral bleaching over vast areas.

The greatest risk comes from multiple pressures acting together

Climate change does not act in isolation. Deforestation, pollution, overfishing, habitat fragmentation and invasive species all reduce the ability of ecosystems to adapt. The IPCC stresses that climate change increasingly amplifies these existing pressures.

What happens next depends on how much warming occurs

The risks rise with every additional increment of warming. The IPCC estimates that at 1.5°C of global warming, around 3 to 14% of assessed terrestrial species could face very high extinction risk. That range grows as warming increases.

The direction is already clear: vegetation zones are moving, seasonal cycles are shifting, marine ecosystems are reorganising and animals are following the climate where they can. The biggest danger is for species that cannot move fast enough, cannot find suitable habitat, or depend on other species that are changing at a different pace.