Polar bears and grizzlies can mate to give birth to grolar bears
WE ALL KNOW ABOUT RISING TEMPERATURES AND MELTING ICE CAPS, BUT WHOEVER HEARD OF THE GROLAR BEAR? HERE ARE SOME OF THE LESSER-KNOWN IMPACTS OF CLIMATE CHANGE
GROLAR BEARS
Some say ‘grolar’, others prefer ‘pizzly’. Whichever it is, this grizzly-polar bear cross, or hybrid, is the result of two habitats colliding under the influence of climate change. While melting sea ice is forcing the remaining polar bears ashore, the previously frigid Arctic is becoming increasingly bearable to grizzlies venturing north.
Encounters with grolar bears – including one shot by a hunter in northern Canada in 2016 – seem to be on the rise, suggesting the two species may be mating more often. The hybrid bears are fertile, so there’s been talk of a new species emerging. However, Dr Andrew Derocher, a bear biologist from the University of Alberta, Canada, doubts this will happen. “Predicting evolution is a fool’s game,” he admits. “However, my best guess is that we won’t see a new species. Grizzly bears could easily absorb a bit of polar bear DNA and keep on going.” In fact, he adds, grizzlies in some of the islands off the north coast of Venezuela have carried DNA from polar bears since polar bears were further south tens of thousands of years ago. A 2017 study suggests that hybrids prefer to mate with grizzlies over polar bears, which should protect the polar genome – though polar bears themselves may die out. Other climate-driven crosses include a number of different seal hybrids, as well as beluga-narwhal whales spotted in western Greenland.
MORE MURDERS
Crime and aggressive behaviour are often noted to increase during heatwaves. This could be a physical reaction to changes in, for example, heart rate and hormone levels, or it could be a psychological reaction caused by discomfort and stress; scientists are still trying to work it out. In 2014, however, a study in the Journal Of Environmental Economics
And Management went one step further, predicting that climate change in the US will cause 22,000 more murders, 180,000 more rapes and 1.2 million more aggravated assaults between 2010 and 2099. Researchers have even tied wars and the collapse of societies such as the Mayans to climatic changes.
WORSE-TASTING COFFEE ( AND WINE, AND BEER!)
Changes in weather patterns will leave less land suitable for coffee-farming. Half of Ethiopia’s coffee-growing regions could be lost, and those areas most suited to coffee production will be the hardest hit, according to one 2017 study. The changing climate will affect other drinks, too. Some craft beers need cool overnight temperatures to draw in wild yeasts from the air, while in vineyards, temperature determines when the grape harvest starts. So far, hotter summers have made for earlier harvests and better-tasting wines, but experts think we’ll soon reach a point where the heat, coupled with increasing rainfall, will reduce quality.
WORSE ALLERGIES
There’s bad news for those of us who suffer from sneezing or wheezing. Hotter summers and higher levels of carbon dioxide encourage plants to produce more pollen for a longer stretch of the year. Climate change is also interfering with the spread of pollution, which can trigger asthma symptoms. These changes could lead to more frequent and intense episodes of hayfever and asthma, the World Allergy Organization warned in 2015.
MORE LIGHTNING
Lightning strikes will increase by about 12 per cent for every 1°C rise in temperature, according to a study in
Science. In theory, a warmer atmosphere is capable of holding on to more moisture, which creates conditions more conducive to lightning. Additional strikes could pose a serious risk as lightning also sparks off wildfires.
MESSED-UP MARINE SOUNDS
In water, sound travels faster at warmer temperatures. If the ocean is warmer or colder than we expect, it throws out our underwater communications systems. This could lead to problems finding an aeroplane’s black box, or make it hard to avoid whales and dolphins. It could also interfere with animals’ own communication systems, crucial in mating and migration. Researchers have already discovered an area of the Arctic Ocean where sound travels four times further than it did a decade ago.
TINY ANIMALS
Animals shrink during periods of warming. Over generations, that is, not before your eyes. It’s thought to be because increasing their surfacearea-to-volume ratio makes them more efficient at getting rid of heat, though whether this happens through natural selection or other factors such as lack of food isn’t known.
Last year, Abigail Carroll of the University of New Hampshire published a study on prehistoric ‘dwarfing’ based on fossils from mammals similar to horses, rabbits, lemurs and weasels. During two hot periods around 54 million years ago, these animals tended to be tinier than at other times in the fossil record, but not quite as tiny, the study found, as during an even hotter period around two million years earlier. She says the same thing is likely to happen under current global warming. “There are already mammals that seem to be responding in this way,” she says. “The red squirrel in California is showing it, and the red deer.” She adds that domesticated animals like horses and dogs will be far slower to respond as they’re under our influence more than that of the climate. Meanwhile, in the event that climate change causes a mass extinction, some scientists are predicting (somewhat dubiously) that we will see scavengers such as gigantic rats evolve in order to fill any empty niches.
MIGRATING NORTH POLE
Climate change is shaking our world to its core, almost literally. Changes to the way water is distributed across the planet – including the melting of the Greenland and Antarctic ice sheets, which contain 99 per cent of the world’s freshwater ice – are shifting the Earth’s axis. Although the axis hasn’t always stayed put, recent changes caused by humans are altering its trajectory. Since 2000, the North Pole has been heading in the direction of continental Europe at a rate of about 16 to 18 centimetres a year. If this continues, geographic north, which is calculated from the long-term average position of the Earth’s rotational axis, may eventually have to be updated. (Though a compass will always point towards magnetic north.) The shift itself may not be too concerning, but it is yet another reminder of our influence on the planet.
BUMPIER PLANE RIDES
Jet-setters, beware. Travelling by plane could be riskier in the future due to an invisible type of turbulence. Clear-air turbulence is increasing because of the way the jet stream – a fast-flowing air current high up in the atmosphere – is speeding up as a result of climate change, explains Prof Paul Williams, who studies atmospheric sciences at the University of Reading. “We have evidence that the jet stream over the north Atlantic, at flight levels, is blowing at a few miles an hour faster than it was a few decades ago,” he says. The faster the jet stream blows, the more likely the air is to become unstable, and when it becomes unstable, it results in turbulence. Clear-air turbulence is more dangerous than turbulence created by clouds because pilots can’t spot it ahead of the plane, so the seatbelt sign is usually off. Williams is one of the authors of a recent study that predicts a doubling of clear-air turbulence over North America, Europe and the North Pacific by the end of this century. Laser detection systems offer a possible solution, but they’re currently heavy and expensive. “It would cost an airline more money to retrofit their fleet with this technology than they would save from the avoided injuries,” says Williams.
DISRUPTED SEX LIVES
Rising temperatures could have a profound influence on the sex lives of reptiles, making it harder for them to find a mate. In green sea turtles, for example, hatchlings from eggs incubated above 29°C are female, while those from eggs incubated at cooler temperatures are male. Populations are usually femaledominated, but in 2016, a study in the Caribbean found that only 16 per cent of green sea turtles are male, and predicted that by 2030, the percentage will fall to just 2 per cent due to climate change.