Posts tagged climate change
Posts tagged climate change
As many as 400,000 people turned out in New York City on Sunday for the People’s Climate March, the largest environmental protest in history. With a turnout far exceeding expectations, the streets of midtown Manhattan were filled with environmentalists, politicians, musicians, students, farmers, celebrities, nurses and labor activists — all united in their demand for urgent action on climate change.
In 36 different US cities with bike share programs, there have been no fatalities on bike share bicycles, and general accident rates are very low.
A mysterious giant virus buried for 30,000 years in Siberian permafrost has been resurrected.
The virus only infects single-celled organisms and doesn’t closely resemble any known pathogens that harm humans.
Even so, the new discovery raises the possibility that as the climate warms and exploration expands in long-untouched regions of Siberia, humans could release ancient or eradicated viruses. These could include Neanderthal viruses or even smallpox that have lain dormant in the ice for thousands of years.
In recent years, Claverie and his colleagues have discovered a host of giant viruses, which are as big as bacteria but lack characteristic cellular machinery and metabolism of those microorganisms. At least one family of these viruses likely evolved from single-celled parasites after losing essential genes, although the origins of other giant viruses remain a mystery, Claverie said. [Tiny Grandeur: Stunning Images of the Very Small]
The findings raise the possibility that other long-dormant or eradicated viruses could be resurrected from the Arctic. As the climate warms and sea ice and permafrost melt, oil and mining companies are drilling many formerly off-limit areas in Russia, raising the possibility that ancient human viruses could be released.
For instance, Neanderthals and humans both lived in Siberia as recently as 28,000 years ago, and some of the diseases that plagued both species may still be around.
"If viable virions are still there, this is a good recipe for disaster," Claverie said. "Virions" is the term used for the virus particles when they are in their inert or dormant form.
Doom…despair…agony on end…deep, dark depression…finally, setting in…
Stupid Politicians - Stupid Financial Authorities - Stupidity in Power
I just want to highlight this illuminating infographic by James Powell in which, based on more than 2000 peer-reviewed publications, he counts the number of authors from November, 2012 to December, 2013 who explicitly deny global warming (that is, who propose a fundamentally different reason for temperature rise than anthropogenic CO2). The number is exactly one. In addition Powell also has helpful links to the abstracts and main text bodies of the relevant papers.
It’s worth noting how many authors agree with the basic fact of global warming – more than nine thousand. And that’s just in a single year. Now I understand as well as anyone else that consensus does not imply truth but I find it odd how there aren’t even a handful of scientists who deny global warming presumably because the global warming mafia threatens to throttle them if they do. It’s not like we are seeing a 70-30% split, or even a 90-10% split. No, the split is more like 99.99-0.01%.
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Of all the threats looming over the planet today, one of the most alarming is the seemingly inexorable descent of the world’s oceans into ecological perdition. Over the last several decades, human activities have so altered the basic chemistry of the seas that they are now experiencing evolution in reverse: a return to the barren primeval waters of hundreds of millions of years ago.
A visitor to the oceans at the dawn of time would have found an underwater world that was mostly lifeless. Eventually, around 3.5 billion years ago, basic organisms began to emerge from the primordial ooze. This microbial soup of algae and bacteria needed little oxygen to survive. Worms, jellyfish, and toxic fireweed ruled the deep. In time, these simple organisms began to evolve into higher life forms, resulting in the wondrously rich diversity of fish, corals, whales, and other sea life one associates with the oceans today.
Yet that sea life is now in peril. Over the last 50 years — a mere blink in geologic time — humanity has come perilously close to reversing the almost miraculous biological abundance of the deep. Pollution, overfishing, the destruction of habitats, and climate change are emptying the oceans and enabling the lowest forms of life to regain their dominance. The oceanographer Jeremy Jackson calls it “the rise of slime”: the transformation of once complex oceanic ecosystems featuring intricate food webs with large animals into simplistic systems dominated by microbes, jellyfish, and disease. In effect, humans are eliminating the lions and tigers of the seas to make room for the cockroaches and rats.
The prospect of vanishing whales, polar bears, bluefin tuna, sea turtles, and wild coasts should be worrying enough on its own. But the disruption of entire ecosystems threatens our very survival, since it is the healthy functioning of these diverse systems that sustains life on earth. Destruction on this level will cost humans dearly in terms of food, jobs, health, and quality of life. It also violates the unspoken promise passed from one generation to the next of a better future.
Humans are eliminating the lions and tigers of the seas to make room for the cockroaches and rats.
The oceans’ problems start with pollution, the most visible forms of which are the catastrophic spills from offshore oil and gas drilling or from tanker accidents. Yet as devastating as these events can be, especially locally, their overall contribution to marine pollution pales in comparison to the much less spectacular waste that finds its way to the seas through rivers, pipes, runoff, and the air. For example, trash — plastic bags, bottles, cans, tiny plastic pellets used in manufacturing — washes into coastal waters or gets discarded by ships large and small. This debris drifts out to sea, where it forms epic gyres of floating waste, such as the infamous Great Pacific Garbage Patch, which spans hundreds of miles across the North Pacific Ocean.
The most dangerous pollutants are chemicals. The seas are being poisoned by substances that are toxic, remain in the environment for a long time, travel great distances, accumulate in marine life, and move up the food chain. Among the worst culprits are heavy metals such as mercury, which is released into the atmosphere by the burning of coal and then rains down on the oceans, rivers, and lakes; mercury can also be found in medical waste.
Hundreds of new industrial chemicals enter the market each year, most of them untested. Of special concern are those known as persistent organic pollutants, which are commonly found in streams, rivers, coastal waters, and, increasingly, the open ocean. These chemicals build up slowly in the tissues of fish and shellfish and are transferred to the larger creatures that eat them. Studies by the U.S. Environmental Protection Agency have linked exposure to persistent organic pollutants to death, disease, and abnormalities in fish and other wildlife. These pervasive chemicals can also adversely affect the development of the brain, the neurologic system, and the reproductive system in humans.
Then there are the nutrients, which increasingly show up in coastal waters after being used as chemical fertilizers on farms, often far inland. All living things require nutrients; excessive amounts, however, wreak havoc on the natural environment. Fertilizer that makes its way into the water causes the explosive growth of algae. When these algae die and sink to the sea floor, their decomposition robs the water of the oxygen needed to support complex marine life. Some algal blooms also produce toxins that can kill fish and poison humans who consume seafood.
The result has been the emergence of what marine scientists call “dead zones” — areas devoid of the ocean life people value most. The high concentration of nutrients flowing down the Mississippi River and emptying into the Gulf of Mexico has created a seasonal offshore dead zone larger than the state of New Jersey. An even larger dead zone — the world’s biggest — can be found in the Baltic Sea, which is comparable in size to California. The estuaries of China’s two greatest rivers, the Yangtze and the Yellow, have similarly lost their complex marine life. Since 2004, the total number of such aquatic wastelands worldwide has more than quadrupled, from 146 to over 600 today.
TEACH A MAN TO FISH — THEN WHAT?
Another cause of the oceans’ decline is that humans are simply killing and eating too many fish. A frequently cited 2003 study in the journal Nature by the marine biologists Ransom Myers and Boris Worm found that the number of large fish — both open-ocean species, such as tuna, swordfish, and marlin, and large groundfish, such as cod, halibut, and flounder — had declined by 90 percent since 1950. The finding provoked controversy among some scientists and fishery managers. But subsequent studies have confirmed that fish populations have indeed fallen dramatically.
In fact, if one looks back further than 1950, the 90 percent figure turns out to be conservative. As historical ecologists have shown, we are far removed from the days when Christopher Columbus reported seeing large numbers of sea turtles migrating off the coast of the New World, when 15-foot sturgeon bursting with caviar leaped from the waters of the Chesapeake Bay, when George Washington’s Continental army could avoid starvation by feasting on swarms of shad swimming upriver to spawn, when dense oyster beds nearly blocked the mouth of the Hudson River, and when the early-twentieth-century American adventure writer Zane Grey marveled at the enormous swordfish, tuna, wahoo, and grouper he found in the Gulf of California.
Today, the human appetite has nearly wiped those populations out. It’s no wonder that stocks of large predator fish are rapidly dwindling when one considers the fact that one bluefin tuna can go for hundreds of thousands of dollars at market in Japan. High prices — in January 2013, a 489-pound Pacific bluefin tuna sold for $1.7 million at auction in Tokyo — make it profitable to employ airplanes and helicopters to scan the ocean for the fish that remain; against such technologies, marine animals don’t stand a chance.
Nor are big fish the only ones that are threatened. In area after area, once the long-lived predatory species, such as tuna and swordfish, disappear, fishing fleets move on to smaller, plankton-eating fish, such as sardines, anchovy, and herring. The overexploitation of smaller fish deprives the larger wild fish that remain of their food; aquatic mammals and sea birds, such as ospreys and eagles, also go hungry. Marine scientists refer to this sequential process as fishing down the food chain.
The problem is not just that we eat too much seafood; it’s also how we catch it. Modern industrial fishing fleets drag lines with thousands of hooks miles behind a vessel, and industrial trawlers on the high seas drop nets thousands of feet below the sea’s surface. In the process, many untargeted species, including sea turtles, dolphins, whales, and large sea birds (such as albatross) get accidentally captured or entangled. Millions of tons of unwanted sea life is killed or injured in commercial fishing operations each year; indeed, as much as a third of what fishermen pull out of the waters was never meant to be harvested. Some of the most destructive fisheries discard 80 to 90 percent of what they bring in. In the Gulf of Mexico, for example, for every pound of shrimp caught by a trawler, over three pounds of marine life is thrown away.
As the oceans decline and the demand for their products rises, marine and freshwater aquaculture may look like a tempting solution. After all, since we raise livestock on land for food, why not farm fish at sea? Fish farming is growing faster than any other form of food production, and today, the majority of commercially sold fish in the world and half of U.S. seafood imports come from aquaculture. Done right, fish farming can be environmentally acceptable. But the impact of aquaculture varies widely depending on the species raised, methods used, and location, and several factors make healthy and sustainable production difficult. Many farmed fish rely heavily on processed wild fish for food, which eliminates the fish-conservation benefits of aquaculture. Farmed fish can also escape into rivers and oceans and endanger wild populations by transmitting diseases or parasites or by competing with native species for feeding and spawning grounds. Open-net pens also pollute, sending fish waste, pesticides, antibiotics, uneaten food, diseases, and parasites flowing directly into the surrounding waters.
DESTROYING THE EARTH’S FINAL FRONTIER
Yet another factor driving the decline of the oceans is the destruction of the habitats that have allowed spectacular marine life to thrive for millennia. Residential and commercial development have laid waste to once-wild coastal areas. In particular, humans are eliminating coastal marshes, which serve as feeding grounds and nurseries for fish and other wildlife, filter out pollutants, and fortify coasts against storms and erosion.
Hidden from view but no less worrying is the wholesale destruction of deep-ocean habitats. For fishermen seeking ever more elusive prey, the depths of the seas have become the earth’s final frontier. There, submerged mountain chains called seamounts — numbering in the tens of thousands and mostly uncharted — have proved especially desirable targets. Some rise from the sea floor to heights approaching that of Mount Rainier, in Washington State. The steep slopes, ridges, and tops of seamounts in the South Pacific and elsewhere are home to a rich variety of marine life, including large pools of undiscovered species.
Today, fishing vessels drag huge nets outfitted with steel plates and heavy rollers across the sea floor and over underwater mountains, more than a mile deep, destroying everything in their path. As industrial trawlers bulldoze their way along, the surfaces of seamounts are reduced to sand, bare rock, and rubble. Deep cold-water corals, some older than the California redwoods, are being obliterated. In the process, an unknown number of species from these unique islands of biological diversity — which might harbor new medicines or other important information — are being driven extinct before humans even get a chance to study them.
Relatively new problems present additional challenges. Invasive species, such as lionfish, zebra mussels, and Pacific jellyfish, are disrupting coastal ecosystems and in some cases have caused the collapse of entire fisheries. Noise from sonar used by military systems and other sources can have devastating effects on whales, dolphins, and other marine life. Large vessels speeding through busy shipping lanes are also killing whales. Finally, melting Arctic ice creates new environmental hazards, as wildlife habitats disappear, mining becomes easier, and shipping routes expand.
IN HOT WATER
As if all this were not enough, scientists estimate that man-made climate change will drive the planet’s temperature up by between four and seven degrees Fahrenheit over the course of this century, making the oceans hotter. Sea levels are rising, storms are getting stronger, and the life cycles of plants and animals are being upended, changing migration patterns and causing other serious disruptions.
Global warming has already devastated coral reefs, and marine scientists now foresee the collapse of entire reef systems in the next few decades. Warmer waters drive out the tiny plants that corals feed on and depend on for their vivid coloration. Deprived of food, the corals starve to death, a process known as “bleaching.” At the same time, rising ocean temperatures promote disease in corals and other marine life. Nowhere are these complex interrelationships contributing to dying seas more than in fragile coral ecosystems.
The oceans have also become more acidic as carbon dioxide emitted into the atmosphere dissolves in the world’s water. The buildup of acid in ocean waters reduces the availability of calcium carbonate, a key building block for the skeletons and shells of corals, plankton, shellfish, and many other marine organisms. Just as trees make wood to grow tall and reach light, many sea creatures need hard shells to grow and also to guard against predators.
On top of all these problems, the most severe impact of the damage being done to the oceans by climate change and ocean acidification may be impossible to predict. The world’s seas support processes essential to life on earth. These include complex biological and physical systems, such as the nitrogen and carbon cycles; photosynthesis, which creates half of the oxygen that humans breathe and forms the base of the ocean’s biological productivity; and ocean circulation. Much of this activity takes place in the open ocean, where the sea and the atmosphere interact. Despite flashes of terror, such as the Indian Ocean earthquake and tsunami of 2004, the delicate balance of nature that sustains these systems has remained remarkably stable since well before the advent of human civilization.
But these complex processes both influence and respond to the earth’s climate, and scientists see certain recent developments as red flags possibly heralding an impending catastrophe. To take one example, tropical fish are increasingly migrating to the cooler waters of the Arctic and Southern oceans. Such changes may result in extinctions of fish species, threatening a critical food source especially in developing countries in the tropics. Or consider that satellite data show that warm surface waters are mixing less with cooler, deeper waters. This reduction in vertical mixing separates near-surface marine life from the nutrients below, ultimately driving down the population of phytoplankton, which is the foundation of the ocean’s food chain. Transformations in the open ocean could dramatically affect the earth’s climate and the complex processes that support life both on land and at sea. Scientists do not yet fully understand how all these processes work, but disregarding the warning signs could result in grave consequences.
A WAY FORWARD
Governments and societies have come to expect much less from the sea. The base lines of environmental quality, good governance, and personal responsibility have plummeted. This passive acceptance of the ongoing destruction of the seas is all the more shameful given how avoidable the process is. Many solutions exist, and some are relatively simple. For example, governments could create and expand protected marine areas, adopt and enforce stronger international rules to conserve biological diversity in the open ocean, and place a moratorium on the fishing of dwindling fish species, such as Pacific bluefin tuna. But solutions will also require broader changes in how societies approach energy, agriculture, and the management of natural resources. Countries will have to make substantial reductions in greenhouse gas emissions, transition to clean energy, eliminate the worst toxic chemicals, and end the massive nutrient pollution in watersheds.
These challenges may seem daunting, especially for countries focused on basic survival. But governments, international institutions, nongovernmental organizations, scholars, and businesses have the necessary experience and capacity to find answers to the oceans’ problems. And they have succeeded in the past, through innovative local initiatives on every continent, impressive scientific advances, tough environmental regulation and enforcement, and important international measures, such as the global ban on the dumping of nuclear waste in the oceans.
So long as pollution, overfishing, and ocean acidification remain concerns only for scientists, however, little will change for the good. Diplomats and national security experts, who understand the potential for conflict in an overheated world, should realize that climate change might soon become a matter of war and peace. Business leaders should understand better than most the direct links between healthy seas and healthy economies. And government officials, who are entrusted with the public’s well-being, must surely see the importance of clean air, land, and water.
The world faces a choice. We do not have to return to an oceanic Stone Age. Whether we can summon the political will and moral courage to restore the seas to health before it is too late is an open question. The challenge and the opportunity are there.
Some 1.2 billion people—almost one fifth of the world—live in areas of physical water scarcity, while another 1.6 billion face what can be called economic water shortage. The situation is only expected to worsen as population growth, climate change, investment and management shortfalls, and inefficient use of existing resources restrict the amount of water available to people. It is estimated that by 2025 fully 1.8 billion people will live in countries or regions with absolute water scarcity, with almost half of the world living in conditions of water stress.
The scale and rate of the present day carbon perturbation, and resulting ocean acidification, is unprecedented in Earth’s known history. Today’s rate of carbon release, at approximately 30Gt of CO2 per year, is at least 10 times faster than that which preceded the last major species extinction (the Paleocene Eocene Thermal Maximum extinction, or PETM, ca. 55 million years ago), while geological records indicate that the current acidification is unparalleled in at least the last 300 million years. We are entering an unknown territory of marine ecosystem change, and exposing organisms to intolerable evolutionary pressure. The next mass extinction event may have already begun.
Today’s explosive increase in human CO2 emissions and warming of the oceans are recreating the conditions of the great Permian extinction 300 million years ago when massive volcanic eruptions in Siberia triggered the release of enormous amounts of stored carbon. A leading theory is that deoxygenation and acidification of the oceans led to the bacterial production of toxic hydrogen sulfide gas which poisoned species dependent on oxygen. By the end of this natural catastrophe 90% to 95% of all marine species were extinct. The biodiversity of the oceans took 30 million years for to recover.
The world’s top climate scientists on Friday formally embraced an upper limit on greenhouse gases for the first time, establishing a target level at which humanity must stop spewing them into the atmosphere or face irreversible and potentially catastrophic climatic changes. They warned that the target is likely to be exceeded in a matter of decades unless steps are taken soon to reduce emissions.
Unveiling the latest United Nations assessment of climate science, the experts cited a litany of changes that are already under way, warned that they are likely to accelerate and expressed virtual certainty that human activity is the main cause.
“Climate change is the greatest challenge of our time,” said Thomas F. Stocker, co-chairman of the Intergovernmental Panel on Climate Change, the United Nations-sponsored group of scientists that produced the report. “In short, it threatens our planet, our only home.”
The panel, in issuing its most definitive assessment yet of the risks of human-caused warming, hoped to give impetus to international negotiations toward a new climate treaty, which have languished in recent years in a swamp of technical and political disputes. The group made clear that time is not on the planet’s side if emissions continue unchecked.
“Human influence has been detected in warming of the atmosphere and the ocean, in changes in the global water cycle, in reductions in snow and ice, in global mean sea level rise, and in changes in some climate extremes,” the report said. “It is extremely likely that human influence has been the dominant cause of the observed warming since the mid-20th century.”
Despite the urgency of the panel’s findings, the course of future international negotiations remains unclear and heated opposition both to established climate science and to strong actions to reduce emissions is certain to continue.
Going well beyond its four previous analyses of the emissions problem, the panel endorsed a “carbon budget” for humanity — a limit on the amount of the primary greenhouse gas, carbon dioxide, that can be produced by industrial activities and the clearing of forests.
To stand the best chance of keeping the planetary warming below an internationally agreed target of 3.6 degrees Fahrenheit (2 degrees Celsius) above the level of preindustrial times, the panel found, no more than one trillion metric tons of carbon can be burned and the resulting gas released into the atmosphere.
Just over half that amount has already been emitted since the beginning of the Industrial Revolution, and at the rate energy consumption is growing, the trillionth ton will be released somewhere around 2040, according to calculations by Myles R. Allen, a scientist at the University of Oxford and one of the authors of the new report. More than three trillion tons of carbon are still left in the ground as fossil fuels.
To keep using fossil fuels beyond the trillionth ton of emissions, companies would have to develop potentially expensive technology to capture and store carbon dioxide from emissions sources like power plants. Such efforts have been lagging badly; only last week, Norway scaled back one of the most ambitious such projects because of soaring costs.
But a considerable body of research suggests that in principle it could be done, and in the United States, the Obama administration is moving toward rules that would essentially require utilities to develop the technology if they want to keep burning coal to produce electricity. In response, the president’s Republican opponents have accused him of waging a “war on coal.”
The report is a 30-page synopsis of a larger, 900-page report that is to be released next week on the physical science of climate change. That will be followed by additional reports in 2014 on the likely impacts and on possible steps to limit the damage.
The group has now issued five major reports since 1990, each of them finding greater certainty that the world is warming and greater likelihood that human activity is the chief cause. The new report finds a 95 to 100 percent chance that most of the warming of recent decades is human-caused, up from the 90 to 100 percent chance cited in the last report, in 2007.
But the new document also acknowledges that climate science still contains huge uncertainties, including the likely magnitude of the warming for a given level of emissions, the rate at which the ocean will rise, and the likelihood that plants and animals will be driven to extinction. The scientists emphasized, however, that those uncertainties cut in both directions and the only way to limit the risk is to limit emissions.
The group won the Nobel Peace Prize in 2007, along with Al Gore, the former vice president, for highlighting the climate problem. But it came under attack in recent years by climate-skeptic organizations, who assailed the new report as alarmist even before it was published.
The Heartland Institute, a Chicago organization that once compared climate scientists to the Unabomber, issued a document last week saying that any additional global warming would likely be limited to a few tenths of a degree and this “would not represent a climate crisis.”
The new report did not take direct aim at such climate doubters, but it did curtly dismiss some of their favorite theories, like the notion that cosmic rays are warming the planet.
On an issue much cited by the climate doubters, a slowdown in global warming that has occurred over the past 15 years, the report acknowledged that it was not fully understood, but said such pauses had occurred in the past and the natural variability of climate was a likely explanation.
“People think that global warming means every year is going to be warmer than the year before,” said Gerald A. Meehl, an American scientist who helped write the report. “It doesn’t work that way. It’s more like a stair-step kind of thing.”
Climate scientists not involved in writing the new report said that the authors had made a series of cautious choices in their assessment of the scientific evidence.
Regarding sea level rise, for instance, they gave the first firm estimates ever contained in an intergovernmental panel report, declaring that if emissions continue at a rapid pace, the rise by the end of the 21st century could be as much as three feet. They threw out a string of published papers suggesting a worst-case rise closer to five feet.
Similarly, the authors went out of their way to include a recent batch of papers suggesting the earth might be somewhat less sensitive to carbon dioxide emissions than previously thought, even though serious questions have been raised about the validity of those estimates.
The new report lowered the bottom end of the range of potential warming that could be expected to occur over the long term if the carbon dioxide level in the atmosphere were to double, reversing a decision the panel made in the last report and restoring a scientific consensus that had prevailed from 1979 to 2007. Six years ago, that range was reported as 3.6 to 8.1 degrees Fahrenheit; the new range is 2.7 to 8.1 degrees.
In Washington, the White House praised the new report. President Obama’s science adviser, John P. Holdren, cited increased scientific confidence “that the kinds of harm already being experienced from climate change will continue to worsen unless and until comprehensive and vigorous action to reduce emissions is undertaken worldwide.”
Ban Ki-moon, the United Nations secretary general, spoke to delegates at the meeting Friday by video link, declaring his intention to call a meeting of heads of state in 2014, in a risky attempt to push such a treaty forward. The last such high-level meeting, in Copenhagen in 2009, ended in disarray.
“The heat is on,” Mr. Ban declared. “Now we must act.”
Policy-makers and the media, particularly in the United States, frequently assert that climate science is highly uncertain. Some have used this as an argument against adopting strong measures to reduce greenhouse gas emissions. For example, while discussing a major U.S. Environmental Protection Agency report on the risks of climate change, then-EPA administrator Christine Whitman argued, “As [the report] went through review, there was less consensus on the science and conclusions on climate change” (1). Some corporations whose revenues might be adversely affected by controls on carbon dioxide emissions have also alleged major uncertainties in the science (2). Such statements suggest that there might be substantive disagreement in the scientific community about the reality of anthropogenic climate change. This is not the case.
The scientific consensus is clearly expressed in the reports of the Intergovernmental Panel on Climate Change (IPCC). Created in 1988 by the World Meteorological Organization and the United Nations Environmental Programme, IPCC’s purpose is to evaluate the state of climate science as a basis for informed policy action, primarily on the basis of peer-reviewed and published scientific literature (3). In its most recent assessment, IPCC states unequivocally that the consensus of scientific opinion is that Earth’s climate is being affected by human activities: “Human activities … are modifying the concentration of atmospheric constituents … that absorb or scatter radiant energy. … [M]ost of the observed warming over the last 50 years is likely to have been due to the increase in greenhouse gas concentrations” [p. 21 in (4)].
IPCC is not alone in its conclusions. In recent years, all major scientific bodies in the United States whose members’ expertise bears directly on the matter have issued similar statements. For example, the National Academy of Sciences report, Climate Change Science: An Analysis of Some Key Questions, begins: “Greenhouse gases are accumulating in Earth’s atmosphere as a result of human activities, causing surface air temperatures and subsurface ocean temperatures to rise” [p. 1 in (5)]. The report explicitly asks whether the IPCC assessment is a fair summary of professional scientific thinking, and answers yes: “The IPCC’s conclusion that most of the observed warming of the last 50 years is likely to have been due to the increase in greenhouse gas concentrations accurately reflects the current thinking of the scientific community on this issue” [p. 3 in (5)].
Others agree. The American Meteorological Society (6), the American Geophysical Union (7), and the American Association for the Advancement of Science (AAAS) all have issued statements in recent years concluding that the evidence for human modification of climate is compelling (8).
The drafting of such reports and statements involves many opportunities for comment, criticism, and revision, and it is not likely that they would diverge greatly from the opinions of the societies’ members. Nevertheless, they might downplay legitimate dissenting opinions. That hypothesis was tested by analyzing 928 abstracts, published in refereed scientific journals between 1993 and 2003, and listed in the ISI database with the keywords “climate change” (9).
The 928 papers were divided into six categories: explicit endorsement of the consensus position, evaluation of impacts, mitigation proposals, methods, paleoclimate analysis, and rejection of the consensus position. Of all the papers, 75% fell into the first three categories, either explicitly or implicitly accepting the consensus view; 25% dealt with methods or paleoclimate, taking no position on current anthropogenic climate change. Remarkably, none of the papers disagreed with the consensus position.
Admittedly, authors evaluating impacts, developing methods, or studying paleoclimatic change might believe that current climate change is natural. However, none of these papers argued that point.
This analysis shows that scientists publishing in the peer-reviewed literature agree with IPCC, the National Academy of Sciences, and the public statements of their professional societies. Politicians, economists, journalists, and others may have the impression of confusion, disagreement, or discord among climate scientists, but that impression is incorrect.
The scientific consensus might, of course, be wrong. If the history of science teaches anything, it is humility, and no one can be faulted for failing to act on what is not known. But our grandchildren will surely blame us if they find that we understood the reality of anthropogenic climate change and failed to do anything about it.
Many details about climate interactions are not well understood, and there are ample grounds for continued research to provide a better basis for understanding climate dynamics. The question of what to do about climate change is also still open. But there is a scientific consensus on the reality of anthropogenic climate change. Climate scientists have repeatedly tried to make this clear. It is time for the rest of us to listen.- Link to Article