Fish and marine mammals are already moving north as sea temperature rises: 'We were astounded by the scale of ocean warming effects on entire ecosystems,' scientists write.
 |
| Gentoo penguins stand on rocks near the Chilean station Bernardo O'Higgins, Antarctica, January 22, 2015. Natacha Pisarenko, AP |
The phenomenon of warming oceans has been somewhat obscured by random fluctuations and our yearning to pretend this isn't happening. But it is. The mean global temperature of the ocean is expected to increase by 1 to 4 degrees by the year 2100, according to the mega-study "Explaining ocean warming: Causes, scale, effects and consequences," compiled by the International Union for Conservation of Nature.
"We were astounded by the scale and extent of ocean warming effects on entire ecosystems made clear by this report," says the coeditor of the 460-page report, Dan Laffoley.
Forecast: Fewer whales, more storms and Zika
The effects of ocean warming already here, and likely future ones include more and stronger super-storms, and the decimation of maritime life as we know it. Experts also expect parasite-borne diseases like malaria and Zika to explode, as pathogens from bacteria to toxic algae proliferate in the warmer clime: Actually, that is already happening.
In fact, all these changes are happening fast. Half of the increase in the mean global ocean temperature since 1865 happened in the last 20 years, according to a January 2016 paper in Nature Climate Change. Moreover, the "warming signal" is reaching deeper into the ocean, wrote the head researcher, Peter Gleckler of the Lawrence Livermore National Laboratory in California.
Even the low-emissions scenario (which is considered unlikely) will profoundly affect marine life, from micro-organisms like plankton to marine mammals like whales and polar bears, according to the report. The big mammals, from whales to walruses, are considered to be especially vulnerable to temperature change.
Why whales? They can just swim away, can't they? Yes, well, "Many whale species are highly migratory and this may put them particularly at risk as they face changes to the multiple environments occupied during their migrations," the IUCN scientists explain. And add: "The problem is that we know ocean warming is driving change in the ocean – this is well documented – but the consequences of these changes decades down the line are far from clear."
 |
| Rare species of Hawaiian coral being used to create a seed bank grows in a tank at a coral nursery in Honolulu, February 2016. Caleb Jones / AP |
Forecast: Jellyfish under northern lights
Forecasting is for the birds. But the likelihood of climate change bringing down hailstones the size of eggs is not small, while the likelihood that it will bring a rain of fairy godmothers can be deemed remote. The likely bottom-line scenario is that ocean warming will bring about catastrophes for which mankind is "completely unprepared," as Inger Andersen, director-general of the IUCN, put it, pleading that greenhouse gas emissions be cut "rapidly and substantially." Otherwise?
"The value of our relationship with the ocean sometimes seems difficult to cost, but is the ultimate relationship that enables life to exist on Earth," says the report. It is time to stop sticking our heads into the ever-hotter sand.
The climbing mean temperature of oceanic waters is already driving species from the microscopic plankton to jellyfish, turtles and seabirds northward, by up to 10 degrees of latitude. Breeding by coastal animals and birds is also being impaired.
The island nation of Japan, for instance, has intensely studied the rising water sea surface temperature and its correlation with the rising incidence, severity and density of jellyfish blooms. Part of the jellyfishes' northward move is ascribed to natural fluctuations, and part to anthropomorphic influences.
Present: Under siege in the Med
Japan isn't alone in experiencing changes in its waters. Temperatures in the shallow Mediterranean Sea, the "miniaturized ocean" on which Israel depends, have been rising especially dramatically since the 1980s, says the report by IUCN. The all-but-enclosed Mediterranean is, therefore, a great model for how climate change affects marine life and biodiversity.
Warming is bad for cold-water lovers: For one, Mediterranean sea fans are all but history. However, the warmth is marvelous for certain creatures: Indeed, hundreds of tropical species – including jellyfish arriving via the Suez Canal, for instance – have been gaining a fin-hold in the Mediterranean ecological cul-de-sac, spurring Israeli oceanographer Bella Galil to call it "a sea under siege." Scientists count at least eight alien species of jellies in the Mediterranean, including the harmless but huge Rhopilema nomadica that has become entirely too familiar to Israeli bathers – and power stations.
 |
| A mosquito control inspector places chemicals into a storm sewer in Miami Beach, Fl., where the Zika virus has been detected, Sept. 2, 2016. Alan Diaz / AP |
In some places, such as the East Africa coastal waters and the western Indian Ocean, on top of overfishing and destructive fishing techniques, the warming has decimated the coral reefs on which the local fish depend. In Southeast Asia, marine harvests are expected to fall by 10 to 30 percent by 2050 relative to 1970-2000, because of changing fish demographics (that's under the high "business as usual" greenhouse gas-emission scenario), the IUCN report predicts.
Tropical and polar fish are especially vulnerable to climate change because they're less tolerant of shifts in environmental temperature. The tropics have become hot spots of ocean warming-driven local extinctions, and if the fish survive at all – they tend to be smaller.
As the scientists note, adverse effects are far likelier than new opportunities. The same applies to seabirds: There are those that will migrate north, but only to a certain degree. Climate change is blamed for decimating emperor penguin populations, which fell 50 percent because of reduced sea ice; rockhopper penguins at Campbell Island declined by 96 percent as sea temperature increased; ivory gull numbers fell 70 percent for the same reasons; Arctic skua breeding numbers in Scotland declined by 74 percent from 1986 to 2011. "Some populations may redistribute polewards, but scope for redistribution is limited," the paper states.
Drought in the Golan
Here's another pretty sure forecast: more rain and storms, if not necessarily where we'd like them. Per degree of global warming, the number of severe hurricanes increases by around 25 to 30 percent, according to the report. Some scientists even expect the frequency of El Nino to increase.
Warming oceans are central to this trend, because more water evaporates from them, and must come down in the form of precipitation. One result has been increased rainfall in mid-latitudes and monsoon areas, and less rain in some subtropical regions. The Indian subcontinent in particular has been slammed by changes in ages-old monsoon patterns.
But life isn't fair and food production, including in North America, is under stress from extreme drought.
Then there's the danger of massive amounts of methane escaping from defrosting "prisons" on the seabed and far north. Methane is a greenhouse gas, and a massive release of it would just accelerate global warming, likely making super-storms all the more frequent and intense.
Can't anything be done? The only way to slow this process – it cannot be simply halted in its tracks any more – is to immediately decarbonize modern society. Stop using oil. Period. And meanwhile?
In the Middle East, the rainy season is winter. Last winter was relatively wet in Israel's arid south, and dry as a bone in the usually wetter Golan Heights. This winter is expected to be so rain-less, in the north and the south, that even though Israel obtains much of its water through desalination, some hydrologists warn that the levels in the freshwater Lake Kinneret and coastal aquifers could sink to dangerous new lows. It's also supposed to be hotter than usual, at least the first half of the winter. The second half is predicted to be colder. And dry as a bone.
Links
- Global warning: ocean warming
- Global warming making oceans sick, spreading disease in humans and animals, scientists warn
- Latest ocean warming review reveals extent of impacts on nature and humans
- Global warming making oceans 'sick', scientists warn
- Latest ocean warming review reveals extent of impacts on nature and humans
No comments :
Post a Comment