If we do not reduce our carbon emissions and instead allow global temperatures to rise by 4.5˚C, up to half of the plants and creatures at a few of the planet’s most biodiverse areas can go extinct by 2100, according to a new analysis. Actually, even if we’re able to limit global warming into the Paris climate arrangement goal of 2˚ C, regions such as the Amazon and the Galapagos could still lose one-quarter of their species, say the investigators, who analyzed the effects of climate change on 80,000 plants and animals in 35 areas. Still another study found that local extinctions (if a species goes extinct in a special area, but still exists elsewhere) are already happening in 47 percent of the 976 species studied, in every type of habitat and climatic zone.
With temperatures climbing, precipitation patterns changing, along the weather becoming more predictable and more intense, a 2016 study decided that climate change is already significantly interrupting organisms and ecosystems on land and in water. Animals are not merely shifting their range and changing the timing of crucial life span — they are also demonstrating differences in their gender ratios, tolerance to heat, and within their own bodies. Some of the changes can enable a species to adapt, though others could speed its demise.
Move, Adapt or Die
Animals can react to climate change in only three ways: They could proceed, adapt or die.
Many animals are moving to higher elevations and latitudes to escape warming temperatures, but climate change may be occurring too quickly for most species to outrun it. Whatever the case, moving is not always an easy solution–entering new land could signify encountering more competition for meals, or interacting with unfamiliar species. Some animals, like the hamster-like American pika, are at the extent of their range. Pikas want the cool moist conditions of the alpine Sierra Nevadas and Western Rockies, but the rugged habitat they require is becoming hotter, drier, and less snowy. Because they already live so high in the mountains, there is nowhere left to go when their terrain becomes inhabitable. Other creatures trying to move to cooler climes may be hemmed in by highways or other manmade structures.
In addition, a few consequences of rising temperatures can not be outrun. Monarch butterflies take their cues from day length and temperature to fly south from Canada into overwintering in Mexico. The butterflies’ southern migration was recently delayed by up to six months because warmer than normal temperatures fail to cue them to fly south.
As temperatures warm, their migrations could fall out of sync with the bloom time of the nectar-producing plants that they rely on for food. Its numbers have decreased by 95% in the previous two decades.
As temperatures rise in the Arctic and sea ice melts, polar bears are also losing their food source; they’re often unable to come across the sea ice they use to search seals from, and rest and breed on. Puffins at the Gulf of Maine generally eat white hake and herring, but as oceans warm, these fish are moving farther north. The puffins are attempting to feed their young on butterfish rather, but baby puffins are not able to swallow the larger fish, so many are starving to death.
Some Species are Adapting
As spring arrives earlier, insects emerge earlier. Some migrating birds have been laying their eggs earlier to match insect availability so their young may have food. Over the past 65 years, the date when female butterflies in southern Australia emerge from their cocoons has changed 1.6 days earlier a decade since temperatures there have warmed 0.14˚C per decade.
Coral reefs, which are actually colonies of individual animals called polyps, have undergone extensive whitening as the oceans warm–when overheated, they expel the vibrant symbiotic algae that live within them. Scientists studying corals around American Samoa discovered that many corals in pools of warmer water had not bleached.
When they exposed these corals to higher temperatures in the laboratory, they found that only 20 percent of them expelled their algae, whereas 55% of corals from cooler pools were additionally exposed to the heat. When corals from a cool pool have been transferred into a hot pool for a year, their warmth tolerance improved–just 32.5 percent now ejected their algae. They adapted with no genetic shift. (“Plasticity” here means flexible or malleable. It has nothing to do with all the hydrocarbon-based products which are clogging our seas and ponds.) The corals living in the hot pools had evolved over several generations as natural selection favored the survival of the very heat-tolerant corals and enabled them to replicate. However, the corals from the pool exposed to the hotter water were also able to accommodate because they’d phenotypic plasticity.