Warmer Rivers Speed Arctic Sea Ice Loss
A once rare butterfly living in the United Kingdom is the latest unexpected beneficiary of the rising temperatures brought about by global climate change. Over the last 25 years, the brown Argus butterfly can now exist over a larger range thanks to a warmer environment and a new plant host to raise its young. And these fortunate insects aren't the only ones who stand to benefit from a warmer world. Yes, over the coming decades, there are certainly many other species, including humans, that will feel increasingly pressured by environmental changes brought about by climate change. But there will be some balance of winners and losers among the different species on this planet. Here's a look at some of those who will likely come out ahead.
Change in wind patterns as a result of climate change has helped albatrosses in the Southern Ocean find food more rapidly, according to a study published in a January 2012 issue of Science. The faster and more intense winds reduce the amount of energy albatrosses need to expend to fly, particularly useful given that these birds can fly distances spanning thousands of miles. By using less energy and finding more food, the albatrosses are healthier and often have better breeding outcomes, according to the study's authors.
Gray Nurse Shark
Worldwide, around one third of oceanic shark species are at risk of extinction, according to the International Union for the Conservation of Nature (IUCN). These animals are primarily at risk as a result of human intervention, particularly the overfishing of sharks for their fins. But there is one species of shark that may stand to benefit from man-made climate change, the Australian gray nurse shark. Like many shark species, gray nurse shark populations have been under pressure. This species could disappear entirely by 2050. However, thanks for warmer waters surrounding Australia, two separate populations of this nurse shark on each side of the continent may reunite for the first time in 100,000 years.
Sharks aren't the only sea life that might benefit from warmer waters. Killer whales, too, appear poised to take advantage of rising ocean temperatures, exploiting new feeding areas as Arctic snow ice melts that were once off limits. The orca's gain, however, could be detrimental to other species. Killer whales prey on two species, the beluga and the narwhale, considered "near threatened" by the IUCN. With their chances to escape to safety from the predatory killer whales dwindling as ice melts, these species could face further pressure to their populations.
This tiny insect has made major inroads into the North American continent thanks to warmer temperatures. Mountain pine beetles can decimate entire forests. During cold snaps, they are killed off. But with shorter, warmer winters, more of these bugs are surviving through the cold season and expanding their ranges even further.
Acidifying oceans and warmer waters might be encouraging swells in populations of jellyfish around the world. Although the notion that jellyfish are benefiting from climate change has been subject to debate, studies have shown that coastal jellyfish populations are generally on the rise. More jellyfish would be bad news for any species that relied on the oceans for its food supply, including humans. Jellyfish can essentially reorder the food web by eating the same plankton that would otherwise be consumed by fish, restricting the transfer of energy on the food chain since predators tend to avoid them. The increase in jellyfish populations could also lead to an ecological disaster by resulting in an increase in carbon beyond what oceans can cope with, according to a report from The Guardian. When jellyfish die, they break down into biomass with considerably higher levels of carbon than their vertebrate counterparts. Bacteria that thrive on decaying organisms cannot absorb carbon as well and instead breathe it out into the atmosphere as carbon dioxide.
U.S. Fish and Wildlife Service
Once standing on the brink of extinction due to over-hunting for their meat and feathers in the 19th century, trumpeter swans have made a comeback in Alaska, thanks not only to restrictions on hunting these birds but also to global warming. Warmer temperatures have allowed the swans to expanding their ranges, and longer summers have allowed to greater opportunities for breeding and raising young, according to Scientific American.
Americans spend some $40 billion a year caring for their lawn, according to Bloomberg News. And that industry could get even more lucrative with the spread of a pest that has its sites set on your home turf: fire ants. According to a report from the National Wildfire Foundation, the range of red imported fire ants could expand some 21 percent in the United States, more than 80 miles northward, within the lifetime of a child born today.
If there's one creature who's climate change gain is our loss, it's mosquitoes. No longer restricted to strictly tropical environments, mosquitoes have spread as warmer temperatures have crept into environments they had never previously been. More mosquitoes means higher potential to spread diseases, including malaria, West Nile virus and dengue fever. This greater risk of disease is not only bad news for humans, but also some animals, including certain bird species, who had previously been unexposed to these pests. In fact, even some of the world's largest creatures are not immune to the disease transmitted by these tiny insects. Last month, the Whale and Dolphin Conservation Society revealed that two whales kept in captivity died as a result of diseases carried by mosquitoes.
Yellow Bellied Marmot
Although most mammals won't be able to flee climate change quickly enough, some are taking full advantage of the changing conditions. The yellow-bellied marmot, which calls Colorado's Rocky Mountains home, fattens up ahead of winter before its long hibernation into spring. With a shorter season though, the marmots are emerging larger than they otherwise would. As a result, they've also been breeding more and passing their larger size onto their offspring.
The downward trend in Arctic sea ice -- in both extent and volume -- is an unmistakable and oft-cited early sign of the impact of climate change. But of course, while the trend lines are clear, there are variations from year to year. For example, 2013 saw the sixth-lowest Arctic sea ice minimum on record, but because that extent was 1.69 million square kilometers (653,000 square miles) above the record minimum -- which was set just the year previously -- climate-change deniers promptly bounced up and down with glee and claimed that Arctic sea ice was “recovering.”
In contrast, 2012 was not only the lowest extent on record, it was the lowest by a lot, much lower even than the previous-record low of 2007, which had itself shattered existing records. The ultimate cause of this sharp decline, of course, was rising temperatures; but according to new research by NASA scientists, the approximate cause was the influx of warm water from Arctic rivers.
Writing in the journal Geophysical Research Letters, a team led by Son Nghiem of NASA’s Jet Propulsion Laboratory describe a sudden influx of warm river waters into the sea in 2012 that rapidly warmed the surface layers of the ocean, enhancing the melting of sea ice.
The team used data from the Moderate Resolution Imaging Spectroradiometer (MODIS) instrument on NASA’s Terra satellite to examine sea ice in the Beaufort Sea, then compared it to reports of river discharge from the Mackenzie River in western Canada.
They found that on June 14, 2012, a stretch of landfast sea ice (sea ice that is stuck to the coastline) formed a barrier that held the river discharge close to its delta. Sometime over the next three weeks, that barrier had disappeared and the average surface temperature of the area of open water in the area increased by 11.7 degrees Fahrenheit (6.5 degrees Celsius).
“When the Mackenzie River’s water is held back behind the sea ice barrier, it accumulates and gets warmer later in the summer,” said Nghiem. “So when it breaks through the barrier, it’s like a strong surge, unleashing warmer waters into the Arctic Ocean that are very effective at melting sea ice. Without this ice barrier, the warm river waters would trickle out little by little, and there would be more time for the heat to dissipate to the atmosphere and to the cooler, deeper ocean.”
According to Nghiem and team, the enhanced river flow is both a result of and contributor to a feedback system of Arctic warming. Increased temperatures lead to ice melt, which causes the collapse of barriers of landfast ice, increasing the volume of river water that enters the Arctic Ocean.
That river water would increase the temperature of the sea water anyway, but is having a greater effect because the rivers are also warming as a result of climate change. In addition, as river heating contributes to earlier and greater loss of the Arctic’s reflective sea ice cover in summer, the amount of solar heat absorbed into the ocean increases, causing even more sea ice to melt.
“If you have an ice cube and drop a few water droplets on it, you’re not going to see rapid melt,” said co-author Dorothy Hall of NASA’s Goddard Space Flight Center in a NASA press release. “But if you pour a pitcher of warm water on the ice cube, it will appear to get smaller before your eyes. When warm river water surges onto sea ice, the ice melts rapidly.”