Wednesday, May 25, 2016
SYDNEY, Australia — Kim Cobb, a marine scientist at the Georgia Institute of Technology, expected the coral to be damaged when she plunged into the deep blue waters off Kiritimati Island, a remote atoll near the center of the Pacific Ocean. Still, she was stunned by what she saw as she descended some 30 feet to the rim of a coral outcropping.
“The entire reef is covered with a red-brown fuzz,” Dr. Cobb said when she returned to the surface after her recent dive. “It is otherworldly. It is algae that has grown over dead coral. It was devastating.”
The damage off Kiritimati is part of a mass bleaching of coral reefs around the world, only the third on record and possibly the worst ever. Scientists believe that heat stress from multiple weather events including the latest, severe El Niño, compounded by climate change, has threatened more than a third of Earth’s coral reefs. Many may not recover.
Coral reefs are the crucial incubators of the ocean’s ecosystem, providing food and shelter to a quarter of all marine species, and they support fish stocks that feed more than one billion people. They are made up of millions of tiny animals, called polyps, that form symbiotic relationships with algae, which in turn capture sunlight and carbon dioxide to make sugars that feed the polyps.
An estimated 30 million small-scale fishermen and women depend on reefs for their livelihoods, more than one million in the Philippines alone. In Indonesia, fish supported by the reefs provide the primary source of protein.
“This is a huge, looming planetary crisis, and we are sticking our heads in the sand about it,” said Justin Marshall, the director of CoralWatch at Australia’s University of Queensland.
Bleaching occurs when high heat and bright sunshine cause the metabolism of the algae — which give coral reefs their brilliant colors and energy — to speed out of control, and they start creating toxins. The polyps recoil. If temperatures drop, the corals can recover, but denuded ones remain vulnerable to disease. When heat stress continues, they starve to death.
Damaged or dying reefs have been found from Réunion, off the coast of Madagascar, to East Flores, Indonesia, and from Guam and Hawaii in the Pacific to the Florida Keys in the Atlantic.
The largest bleaching, at Australia’s Great Barrier Reef, was confirmed last month. In a survey of 520 individual reefs that make up the Great Barrier Reef’s northern section, scientists from Australia’s National Coral Bleaching Task Force found only four with no signs of bleaching. Some 620 miles of reef, much of it previously in pristine condition, had suffered significant bleaching.
In follow-up surveys, scientists diving on the reef said half the coral they had seen had died. Terry Hughes, the director of the Center of Excellence for Coral Reef Studies at James Cook University in Queensland, who took part in the survey, warned that even more would succumb if the water did not cool soon.
“There is a good chance a large portion of the damaged coral will die,” he added.
Scientists say the global bleaching is the result of an unusual confluence of events, each of which raised water temperatures already elevated by climate change.
In the North Atlantic, a strong high-pressure cell blocked the normal southward flow of polar air in 2013, kicking off the first of three warmer-than-normal winters in a row as far south as the Caribbean.
A large underwater heat wave formed in the northeastern Pacific in early 2014, and has since stretched into a wide band along the west coast of North America, from Baja California to the Bering Sea. Nicknamed the Blob, it is up to four degrees Fahrenheit warmer than surrounding waters, and has been blamed for a host of odd phenomena, including the beaching of hungry sea lions in California and the sighting of tropical skipjack tuna off Alaska.
Then came 2015, with the most powerful El Niño climate cycle in a century. It blasted heat across the tropical and southern Pacific, bleaching reefs from Kiritimati to Indonesia, and across the Indian Ocean to Réunion and Tanzania on Africa’s east coast.
“We are currently experiencing the longest global coral bleaching event ever observed,” said C. Mark Eakin, the Coral Reef Watch coordinator at the National Oceanic and Atmospheric Administration in Maryland. “We are going to lose a lot of the world’s reefs during this event.”
Reefs that take centuries to form can be destroyed in weeks. Individual corals may survive a bleaching, but repeated bleachings can kill them.
Lurid reports of damaged reefs started coming in from worried scientists in the summer of 2014.
Lyza Johnston, a marine biologist in the Northern Mariana Islands, dived to the reefs off Maug, a group of small islands: “In every direction, nearly all of the corals were bright white.”
Misaki Takabayashi, a marine scientist at the University of Hawaii at Hilo, surfed the waves above the blue rice coral there: “I could see what looked like bleached white ghosts popping up off the ocean floor at me.”
Cory Walter, a senior biologist at the Mote Marine Laboratory in Florida, peered down from a boat over Wonderland Reef off the Lower Florida Keys: “It almost looks like it snowed on the reef.”
Predicting the duration of the bleaching or forecasting the next one is difficult. The Blob has cooled somewhat, and El Niño, while weakening, is expected to stretch into 2017.
Dr. Eakin, the coral-reef specialist at the National Oceanic and Atmospheric Administration, said he expected the bleaching to continue for nine more months. Scientists will not be able to measure the full extent of the damage until it is over.
What is clear is that these events are happening with increasing frequency — and ferocity. The previous bleachings, in 2010 and 1998, do not appear to have been as extensive or prolonged as the current one.
The 1998 bleaching, which Dr. Eakin said had been set off by a fierce El Niño, killed around 16 percent of the world’s coral. By 2010, oceans had warmed enough that it took only a moderate El Niño to start another round.
Then in 2013, Dr. Eakin said, “a lot of bleaching happened due to climate change, before the El Niño had even kicked in.”
Reefs that were bleached in 2014, like those in the Florida Keys and the Caribbean, had no time to regenerate before suffering further thermal stress from El Niño last year, leaving the coral vulnerable to disease and death.
The reefs in the Florida Keys “are about to go into a third year straight of bleaching, something that has never happened before,” said Meaghan Johnson, a marine scientist at the Nature Conservancy. “We are worried about disease and mortality rates.”
Ove Hoegh-Guldberg, the director of Australia’s Global Change Institute, noted that 2015 was the hottest year ever recorded, both on land and in the oceans — breaking a record set just the year before.
“Rising temperatures due to climate change have pushed corals beyond their tolerance levels,” he said, adding that back-to-back bleaching can be particularly deadly to the corals.
El Niño warms the equatorial waters around Kiritimati Island more than anywhere else in the world, making it a likely harbinger for the health of reefs worldwide. That is why Dr. Cobb, the Georgia Tech scientist who made the recent dive, has been making the trek at least once a year for the past 18 to the tiny atoll, part of the Line Islands archipelago.
Though the atoll sits just north of the Equator, trade winds suck water up from the depths of the ocean, usually keeping the water temperature surrounding the reefs a healthy, nearly constant 78 degrees.
But in 2015, the expected upwelling of deep, cold water did not happen, Dr. Cobb said, speaking by satellite phone after her dive. So water in the atoll was 10 degrees warmer than normal, and never cooled enough to allow coral to recover.
“The worst has happened,” she said. “This shows how climate change and temperature stresses are affecting these reefs over the long haul. This reef may not ever be the same.”
Thursday, May 19, 2016
|Coordinates: 27°50′S 48°25′W|
Sunday, May 15, 2016
Tuesday, April 1, 2014
The costs of inaction on climate change will be "catastrophic", according to US Secretary of State John Kerry.
Mr Kerry was responding to a major report by the UN which described the impacts of global warming as "severe, pervasive and irreversible".
He said dramatic and swift action was required to tackle the threats posed by a rapidly changing climate.
Our health, homes, food and safety are all likely to be threatened by rising temperatures, the report says.
Scientists and officials meeting in Japan say the document is the most comprehensive assessment to date of the impacts of climate change on the world.
In a statement, Mr Kerry said: "Unless we act dramatically and quickly, science tells us our climate and our way of life are literally in jeopardy. Denial of the science is malpractice.
"There are those who say we can't afford to act. But waiting is truly unaffordable. The costs of inaction are catastrophic."
Rajendra Pachauri, chair of the Intergovernmental Panel on Climate Change (IPCC), which produced the report, told BBC News: "Even in rich countries, the impacts of climate change could lead to greater incidents of pockets of poverty, even in rich countries could lead to impoverishment of some particular communities.
"However there is an equity issue, because some of the poorest communities in the poorest countries in the world are going to be the worst hit."
Monday, March 31, 2014
By JUSTIN GILLIS
YOKOHAMA, Japan — Climate change is already having sweeping effects on every continent and throughout the world’s oceans, scientists reported on Monday, and they warned that the problem was likely to grow substantially worse unless greenhouse emissions are brought under control.
The report by the Intergovernmental Panel on Climate Change, a United Nations group that periodically summarizes climate science, concluded that ice caps are melting, sea ice in the Arctic is collapsing, water supplies are coming under stress, heat waves and heavy rains are intensifying, coral reefs are dying, and fish and many other creatures are migrating toward the poles or in some cases going extinct.
The oceans are rising at a pace that threatens coastal communities and are becoming more acidic as they absorb some of the carbon dioxide given off by cars and power plants, which is killing some creatures or stunting their growth, the report found.
Organic matter frozen in Arctic soils since before civilization began is now melting, allowing it to decay into greenhouse gases that will cause further warming, the scientists said. And the worst is yet to come, the scientists said in the second of three reports that are expected to carry considerable weight next year as nations try to agree on a new global climate treaty.
In particular, the report emphasized that the world’s food supply is at considerable risk — a threat that could have serious consequences for the poorest nations.
“Nobody on this planet is going to be untouched by the impacts of climate change,” Rajendra K. Pachauri, chairman of the intergovernmental panel, said at a news conference here on Monday presenting the report.
The report was among the most sobering yet issued by the scientific panel. The group, along with Al Gore, was awarded the Nobel Peace Prize in 2007 for its efforts to clarify the risks of climate change. The report is the final work of several hundred authors; details from the drafts of this and of the last report in the series, which will be released in Berlin in April, leaked in the last few months.
The report attempts to project how the effects will alter human society in coming decades. While the impact of global warming may actually be moderated by factors like economic or technological change, the report found, the disruptions are nonetheless likely to be profound. That will be especially so if emissions are allowed to continue at a runaway pace, the report said.
It cited the risk of death or injury on a wide scale, probable damage to public health, displacement of people and potential mass migrations.
“Throughout the 21st century, climate-change impacts are projected to slow down economic growth, make poverty reduction more difficult, further erode food security, and prolong existing and create new poverty traps, the latter particularly in urban areas and emerging hot spots of hunger,” the report declared.
The report also cited the possibility of violent conflict over land, water or other resources, to which climate change might contribute indirectly “by exacerbating well-established drivers of these conflicts such as poverty and economic shocks.”
The scientists emphasized that climate change is not just a problem of the distant future, but is happening now.
Studies have found that parts of the Mediterranean region are drying out because of climate change, and some experts believe that droughts there have contributed to political destabilization in the Middle East and North Africa.
In much of the American West, mountain snowpack is declining, threatening water supplies for the region, the scientists said in the report. And the snow that does fall is melting earlier in the year, which means there is less melt water to ease the parched summers. In Alaska, the collapse of sea ice is allowing huge waves to strike the coast, causing erosion so rapid that it is already forcing entire communities to relocate.
“Now we are at the point where there is so much information, so much evidence, that we can no longer plead ignorance,” Michel Jarraud, secretary general of the World Meteorological Organization, said at the news conference.
The report was quickly welcomed in Washington, where President Obama is trying to use his executive power under the Clean Air Act and other laws to impose significant new limits on the country’s greenhouse emissions. He faces determined opposition in Congress.
“There are those who say we can’t afford to act,” Secretary of State John Kerry said in a statement. “But waiting is truly unaffordable. The costs of inaction are catastrophic.”
Amid all the risks the experts cited, they did find a bright spot. Since the intergovernmental panel issued its last big report in 2007, it has found growing evidence that governments and businesses around the world are making extensive plans to adapt to climate disruptions, even as some conservatives in the United States and a small number of scientists continue to deny that a problem exists.
“I think that dealing effectively with climate change is just going to be something that great nations do,” said Christopher B. Field, co-chairman of the working group that wrote the report and an earth scientist at the Carnegie Institution for Science in Stanford, Calif. Talk of adaptation to global warming was once avoided in some quarters, on the ground that it would distract from the need to cut emissions. But the past few years have seen a shift in thinking, including research from scientists and economists who argue that both strategies must be pursued at once.
A striking example of the change occurred recently in the state of New York, where the Public Service Commission ordered Consolidated Edison, the electric utility serving New York City and some suburbs, to spend about $1 billion upgrading its system to prevent future damage from flooding and other weather disruptions.
The plan is a reaction to the blackouts caused by Hurricane Sandy. Con Ed will raise flood walls, bury some vital equipment and conduct a study of whether emerging climate risks require even more changes. Other utilities in the state face similar requirements, and utility regulators across the United States are discussing whether to follow New York’s lead.
But with a global failure to limit greenhouse gases, the risk is rising that climatic changes in coming decades could overwhelm such efforts to adapt, the panel found. It cited a particular risk that in a hotter climate, farmers will not be able to keep up with the fast-rising demand for food.
“When supply falls below demand, somebody doesn’t have enough food,” said Michael Oppenheimer, a Princeton University climate scientist who helped write the new report. “When some people don’t have food, you get starvation. Yes, I’m worried.”
The poorest people in the world, who have had virtually nothing to do with causing global warming, will be high on the list of victims as climatic disruptions intensify, the report said. It cited a World Bank estimate that poor countries need as much as $100 billion a year to try to offset the effects of climate change; they are now getting, at best, a few billion dollars a year in such aid from rich countries.
The $100 billion figure, though included in the 2,500-page main report, was removed from a 48-page executive summary to be read by the world’s top political leaders. It was among the most significant changes made as the summary underwent final review during an editing session of several days in Yokohama.
The edit came after several rich countries, including the United States, raised questions about the language, according to several people who were in the room at the time but did not wish to be identified because the negotiations were private. The language is contentious because poor countries are expected to renew their demand for aid this September in New York at a summit meeting of world leaders, who will attempt to make headway on a new treaty to limit greenhouse gases.
Many rich countries argue that $100 billion a year is an unrealistic demand; it would essentially require them to double their budgets for foreign aid, at a time of economic distress at home. That argument has fed a rising sense of outrage among the leaders of poor countries, who feel their people are paying the price for decades of profligate Western consumption.
Two decades of international efforts to limit emissions have yielded little result, and it is not clear whether the negotiations in New York this fall will be any different. While greenhouse gas emissions have begun to decline slightly in many wealthy countries, including the United States, those gains are being swamped by emissions from rising economic powers like China and India.
For the world’s poorer countries, food is not the only issue, but it may be the most acute. Several times in recent years, climatic disruptions in major growing regions have helped to throw supply and demand out of balance, contributing to price increases that have reversed decades of gains against global hunger, at least temporarily.
The warning about the food supply in the new report is much sharper in tone than any previously issued by the panel. That reflects a growing body of research about how sensitive many crops are to heat waves and water stress. The report said that climate change was already dragging down the output of wheat and corn at a global scale, compared with what it would otherwise be.
David B. Lobell, a Stanford University scientist who has published much of the recent research and helped write the new report, said in an interview that as yet, too little work was being done to understand the risk, much less counter it with improved crop varieties and farming techniques. “It is a surprisingly small amount of effort for the stakes,” he said.
Timothy Gore, an analyst for Oxfam, the antipoverty group that sent observers to the proceedings in Yokohama, praised the new report as painting a clear picture of the consequences of a warming planet. But he warned that without greater efforts to limit global warming and to adapt to the changes that have become inevitable, “the goal we have in Oxfam of ensuring that every person has enough food to eat could be lost forever.”