Tuesday, December 15, 2015

On Saturday evening in Paris, France, world leaders finalized a deal to try to stem Earth’s surging temperature. The 2015 Paris Climate Conference, also called COP21, reached an agreement on climate in order to keep global temperatures from rising more than 3.6 °F (2 °C) from levels in the mid-1800’s. COP21 is an acronym for the 21st annual session of the Conference of the Parties. The Paris agreement is a landmark measure in the way that it sets a long-term goal for slowing global warming and provides methods for countries to achieve that goal.

Sunset in Sahara Desert. Credit: © Anna Gibiskys, Shutterstock

Global warming is an increase in the average temperature at Earth’s surface, referring specifically to the warming observed since the mid-1800’s. If it continues unchecked, it may melt ice on land near Earth’s poles, raising sea levels; lead to widespread droughts; and cause certain plant and animal species to become extinct. Natural processes have caused Earth’s climate to change in the distant past. But scientists have found strong evidence that human activities have caused most of the warming since the mid-1900’s. Such activities include the release of greenhouse gases like carbon dioxide into the atmosphere, where they trap heat like a blanket around Earth. Researchers have also found that most of the temperature increase occurred from the mid-1900′s to the 2000′s.

Climate change leaders succeeded in forming the Paris agreement through much skillful compromise. For example, many coastal and island nations—which will be the most affected by climate change—wanted any resolution coming from the Paris talks to be legally binding. Larger, heavier-polluting countries preferred a nonbinding agreement. COP21 reached a compromise where countries are legally required to set and review emissions reduction targets, but the enforcement of those targets by the countries is voluntary. The climate agreement also contains measures for more developed countries to assist less-developed ones in environmentally responsible economic development. Though developing nations were not part of the problem of high greenhouse gas emissions in the past, they must be part of the solution through limited emissions in the future. Economic assistance for these countries will help them improve life for their citizens without negatively impacting the climate.

As in any compromise, no one side got exactly what it wanted. Some environmental groups say that the agreement does not go far enough and will not stop the planet from exceeding the 3.6 °F (2 °C) threshold as it promises, for example. But the Paris agreement represents a turning point in how humanity tackles climate change. Based on the deal outlined over the last two weeks, all countries will do their part to limit their emissions with the hope of slowing the march of climate change.

Additional World Book articles:

• Greenhouse effect
• Holding the Line at 2° (a Behind the Headlines article)
• The Great Meltdown (a special report)
• Probing the History of Climate Change  (a special report)
• What We Know About Climate Change (a special report)

Monday, November 30, 2015

For the next two weeks, officials from 195 countries will meet in Paris to discuss what world governments can do about the problem of climate change. The 2015 Paris Climate Conference, also called COP21, aims to reach an agreement on climate in order to keep global temperatures from rising more than 3.6 °F (2 °C) from levels in the mid-1800’s. COP21 is an acronym for the 21st annual session of the Conference of the Parties.

Sunset in Sahara Desert. Credit: © Anna Gibiskys, Shutterstock

Global warming is an increase in the average temperature at Earth’s surface, referring specifically to the warming observed since the mid-1800’s. If it continues unchecked, it may melt ice on land near Earth’s poles, raising sea levels; lead to widespread droughts; and cause certain plant and animal species to become extinct. Natural processes have caused Earth’s climate to change in the distant past. But scientists have found strong evidence that human activities have caused most of the warming since the mid-1900’s. Such activities include the release of greenhouse gases like carbon dioxide into the atmosphere, where they trap heat like a blanket around Earth.

World governments face many challenges in creating a viable agreement and averting global climate disaster. For instance, countries are divided over whether or not the agreement should be a legally binding treaty. Because of the difficulty of getting such a treaty approved in his home country, U.S. Secretary of State John Kerry said on Wednesday that he did not expect the agreement to be legally binding. Other leaders, however, such as French President François Hollande, have insisted that the agreement must be legally binding so that the international community can ensure that countries meet their targets.

COP21 is focused on preventing temperatures from rising more than 3.6 °F (2 °C) from pre-industrial levels. However, scientists estimate that Earth’s average surface temperature has already risen by about 1.4 °F (0.76 °C). Also, greenhouse gases continue to heat Earth for many years, so global temperatures will continue to rise for decades, even if humans stop producing greenhouse gases today. Furthermore, some scientists and the governments of coastal countries—which would bear the brunt of the impact of climate change—argue that such a temperature increase will still have dire global consequences. Whatever the case, the Paris conference is the best chance humanity has today to avoid further environmental and humanitarian disaster.

Additional World Book articles:

• Greenhouse effect
• The Great Meltdown (a special report)
• Probing the History of Climate Change  (a special report)
• What We Know About Climate Change (a special report)

August 24, 2015

In an August 2015 photo, the sun turns red as it sets through the smoke behind the Olympic Mountains in central Washington. Wildfires in the state left a black, smoky haze hanging over the entire area.
(Credit: © Larry Steagall, Kitsap Sun/AP Photo)

Some 30,000 firefighters, including some who have arrived from Australia, Canada, and New Zealand, are being deployed this week to combat an unprecedented outbreak of wildfires blazing across the United States. In all, 17 states are actively fighting wildfires this August, during one of the driest and most explosive wildfire seasons on record. California, Idaho, Montana, Oregon, and Washington each report that at least 10 large wildfires are currently raging. These wildfires have claimed the lives of 13 firefighters.

A wildfire is the uncontrolled burning of large areas of vegetation. Depending on where they occur, such fires may also be called brushfires, bushfires, or forest fires. Wildfires may be ignited by human activities or by natural causes. Such natural causes include lightning or even intense sunlight. A wildfire can happen in any area with vegetation. Such areas include forests, grasslands, and shrublands. The intensity of a wildfire depends on the type of vegetation fueling it, the terrain, and the weather.

Since January 1, 2015, more than 41,000 individual wildfires in the United States have burned more than 7.2 million acres (2.9 million hectares), mostly in the Pacific Northwest and Alaska. That amount is already almost three times the 2.6 million acres that burned throughout the entire United States in all of 2014. This year’s fires have already burned more land than in any other year over the last decade. This year’s wildfires have been fueled by drought and record high temperatures.

Climate scientists attribute this year’s high temperatures and dry conditions to climate change caused by global warming. Data from the U.S. Forest Service indicates that the fire season, typically occurring over the summer months from June through August, now extends almost year round, averaging 78 days longer compared to fire seasons in the 1970’s. A huge mass of warm water that has settled in the Pacific Ocean off the West Coast of the United States is partially to blame. Climate scientists also point to a warm-water current called El Niño developing in the Pacific. In the United States, El Niño causes the climate to become drier than normal in the Pacific Northwest. Heavier-than-normal winter rains in the region, which often occur with El Niño, provide hope that this wildfire season won’t last.

Other World Book articles

• Bushfires in Australia
• Drought in California (a Special report)

August 4, 2015

Yesterday, August 3, U.S. President Barack Obama unveiled a new initiative to combat climate change, the Clean Power Plan. President Obama called the plan “the biggest, most important step we have ever taken” concerning climate change. The regulations, if approved, will authorize the Environmental Protection Agency (EPA) to regulate power plants that generate electric power in order to reduce carbon emissions by 32 percent by 2030.

The plan will likely hit the coal industry the hardest. About 40 percent of electricity in the United States is generated with coal. The coal is used to heat water, generating steam. This steam turns a turbine, which powers a generator that creates electricity. The problem with coal is that it emits twice as much carbon dioxide into Earth’s atmosphere as does natural gas used for the same purpose. Carbon dioxide is a greenhouse gas that traps heat in Earth’s atmosphere, leading to rising average temperatures.

Coal-burning power plants such as this release carbon dioxide, a major greenhouse gas. Greenhouse gases trap heat, contributing to global warming, an observed increase in Earth’s average surface temperature.© Thinkstock

There are more than 50 major coal mines in the United States. Many of the mines are in West Virginia and Wyoming. So, coal is a domestically produced fuel source, and U.S. states that produce coal will be hurt by any regulation that reduces its use. At one time, using natural gas to fuel power plants would have been very expensive for the United States. But, the development of hydraulic fracturing (fracking) in such U.S. states as North Dakota has caused the cost of natural gas to drop dramatically.

Natural gas is perhaps the easiest fuel source to change out for coal to reduce emissions. Renewable energy, such as wind power and solar power can also be used to generate electricity. Both methods, however, require building an electric-power grid that can move power from remote locations where wind and solar farms are to populated areas where electricity is needed. Nevertheless, such power sources are already being used and will be more used in the future. President Obama stated yesterday, “I’m convinced no challenge provides a greater threat to the future of the planet…There is such a thing as being too late.”

Wind turbines capture energy from moving air—wind—and change it into electrical energy. This photograph shows a wind turbine “farm” in the California desert. © Shutterstock

Other World Book articles:

• Climate
• Global Warming
• Greenhouse effect

January 8, 2015

The first of four official reports on global temperature published annually has concluded that 2014 was the hottest year on record. The Japan Meteorological Agency (JMA) reported that the average global temperature in 2014 was 1.1 Fahrenheit degrees (0.6 Celsius degree) above the average for the 1900′s. That puts 2014 ahead of 1998, the previous warmest year, by about 0.1 Fahrenheit (0.06 Celsius) degree. Additional reports expected soon from the National Oceanic and Atmospheric Administration and NASA in the United States and the Meteorological Office Hadley Centre for Climate Change in the United Kingdom are expected to confirm the JMA’s findings. The four organizations use  ground measurements and satellite data to reach their conclusions. All 10 of Earth’s hottest recorded years have come since 1998. In addition, 14 of the 15 hottest years measured have all occurred since 2000.

Scientists estimate that Earth’s average surface temperature has risen by about 1.4 Fahrenheit degrees (0.76 Celsius degree) from the mid-1800′s to the early 2000′s. Researchers have also found that most of the temperature increase occurred from the mid-1900’s to the 2000’s. Natural processes have caused Earth’s climate to change in the distant past. But strong scientific evidence shows that human activities have caused most of the warming since the mid-1900′s.

The retreat of a mountain glacier can provide visible evidence of global warming. These photographs show two late-summer views of Grinnell Glacier in Glacier National Park, Montana. In the photo taken around 1940 (top) Upper Grinnell Lake had only begun to form at the glacier’s end. By 2006 (bottom), melting ice had caused the lake to swell in size. Researchers predict that warming will melt all of the park’s glaciers by 2030. (Glacier National Park Archives, top, U.S. Geological Survey, photograph by Karen Holtzer, bottom)

According to the JMA, record temperatures in Europe, Australia and other parts of the Pacific region, and California helped drive up global records. Seasonal temperatures also climbed. In 2014, spring, summer and fall all saw global highs. Only winter 2014 failed to enter the record books. However, it was the sixth-warmest winter ever measured.

Additional World Book articles:

• Global warming
• The Great Meltdown (a special report)
• Methane (a special report)
• Meltdown: Climate Change in the Arctic (a special report)
• Probing the History of Climate Change  (a special report)
• What We Know About Climate Change (a special report)

December 3, 2014

The latest study of the West Antarctic Ice Sheet has provided more strong evidence of the devastating effect of global warming on this vulnerable region of Antarctica. The 21-year study found that the melting rate of the ice in the already-unstable Amundsen Sea region has tripled from 2003 to 2009. The findings, reported by scientists at the University of California, Irvine (UCI), and NASA’s Jet Propulsion Laboratory (JPL) in Pasadena, California, are being described as the most authoritative estimate of ice loss in the region.

A number of studies have revealed that the West Antarctic Ice Sheet, which contains Antarctica’s fastest flowing ice, is warming much faster than scientists had estimated and that melting there has accelerated significantly since the early 1990′s. In May 2014, scientists from UCI and JPL reported that glaciers around the Amundsen Sea, the weakest of the continent’s ice sheets, appear to have begun a gradual but “unstoppable” slide into the sea. For the new study, the UCI and JPL scientists compared measurements of the “mass balance” of glaciers flowing into the sea using four different tools, including Earth-orbiting satellites, radars, and lasers. NASA defines mass balance as a measure of how much ice the glaciers gain and lose over time from accumulating or melting snow, discharges of ice as icebergs, and other causes. The scientists found that from 1992 to 2003, the melting rate increased by 6.7 billion tons (6 billion metric tons) of ice each year. From 2003 to 2009, however, the melting rate soared to 18 billion tons (16 billion metric tons) annually. The scientists calculated that the region has shed an amount of ice equal to Mount Everest, the highest mountain in the world, every two years for the past 21 years.

The glaciers in Amundsen Sea region of West Antarctica are losing ice faster than any other glaciers on the continent. (NASA/Michael Studinger)

The West Antarctic Ice Sheet is especially vulnerable to climate change, in part, because most of the ice sheet lies on terrain that is an average of 3,300 feet (1,000 meters) below sea level. As a result, the leading edges, or tongues, of the glaciers float on seawater. When a glacier melts, its grounding line–the point where a glacier attaches to underlying terrain and begins to float–also retreats. Nearly all the melting takes place on the underside of a glacier beyond the grounding line, where the ice comes into contact with warm seawater.

Additional World Book articles:

• Exploration (the Exploration of Antarctica)
• Global warming (2009) (a Back in Time article)
• The Great Meltdown (a special report)
• Science in Antarctica (a special report)

November 4, 2014

Earth faces “severe, pervasive and irreversible impacts for people and ecosystems” if climate change continues at its current rate, according to a summary assessment of some 30,000 studies on climate change by the Intergovernmental Panel on Climate Change (IPCC). A committee of the United Nations, the IPCC provides scientific information to world governments about the impact of human activities on global warming.

According to the new report, cutting the emissions of greenhouse gases, particularly carbon dioxide, is essential to prevent global warming from rising more than 3.6 °F (2 °C) above levels at the start of the Industrial Revolution. This increase in average surface temperatures is widely accepted by scientists as the “tipping point” for devastating climate change. To meet this goal, the IPCC reported, the amount of power obtained from renewable forms of energy must increase from 30 percent to 80 percent of all power by 2050. And unless efficient forms of carbon capture and storage (CCS) are developed, people should quit burning fossil fuels altogether by 2100. Also known as carbon sequestration, CSS involves capturing the carbon dioxide released by burning fossil fuels and storing it in deep underground rock formations.

Levels of atmospheric carbon dioxide (CO2) are higher today than at any time in the past 400,000 years. Although CO2 levels fluctuate naturally, the levels are much higher than they would have been if people were not burning such huge amounts of fossil fuels, including coal, oil, and gas. About 60 percent of fossil-fuel emissions remain in the atmosphere, causing global warming. (National Oceanic and Atmospheric Administration)

The new report, called the Synthesis Report, combines the findings of three assessments released over the past 14 months. Those reports were compiled by more than 800 scientists from 100 countries. One assessment, released in March 2014, concluded that rising global temperatures are threatening the world’s food supplies, intensifying violent storms and droughts, pushing sea levels dangerously higher, and causing serious disruptions in land and ocean ecosystems. In that report, the IPCC also warned for the first time that climate change poses a threat to human security by increasing the risk of violent conflict over natural resources and because of large-scale migrations by people fleeing difficult environmental conditions. In another assessment, released in September 2013, IPCC scientists reported being 95 percent certain that humans are the “dominant cause” of global warming.

The Synthesis Report also offered hope. It noted that the cost of even the most aggressive actions to reduce emissions would have only a small effect on world economic growth in this century. In addition, governments and industry are spending some $200 billion a year less on combating climate change than they are on developing new sources of fossil fuels. “We have the means to limit climate change.” said R. K. Pachauri, chair of the IPCC. “The solutions are many and allow for continued economic and human development. All we need is the will to change. …”

Additional World Book articles:

• The Great Meltdown (a special report)
• Methane (a special report)
• Meltdown: Climate Change in the Arctic (a special report)
• Probing the History of Climate Change  (a special report)
• What We Know About Climate Change (a special report)

July 23, 2014

Wildfires fueled by higher-than-normal temperatures and lower-than-normal rainfall are burning an unusually large swathe of Canada’s Northwest Territories (NWT) this summer. At least 235 fires have consumed nearly 2.2 million acres (900,000 hectares), an area six times as great as the area normally affected each year during the past 25 years. Although the fires have swept across less than 1 percent of the vast NWT, the area burned equals more than the area of the states of Delaware and Rhode Island combined. More than half of the fires are burning out of control, according to the Canadian Interagency Forest Fire Center. The fires have forced hundreds of people from their home. Huge clouds of smoke and ash from the fires have also led Environment Canada, the government’s environmental protection agency, to issue poor-air-quality warnings for parts of the NWT as well as for the provinces of Alberta, Saskatchewan, and Manitoba. The smoke plume from the fires has spread thousands of miles (kilometers) south to North Dakota and South Dakota in the United States.

Daily temperature highs in Yellowknife, the capital and largest city in the NWT, have been running nearly 4 degrees Fahrenheit (2 degrees Celsius) above normal for July, while the city has received only about 2 percent of its average July rainfall. Meteorologists think that most of the fires have been sparked by lightning during “dry thunderstorms.” Such storms occur when the air below the clouds is so dry that any water falling from the clouds evaporates before it hits the ground.

Red dots mark the location of some of the large wildfires charing the Northwest Territories in Canada. Plumes of smoke from the fires have swept south and east through Canada’s prairie provinces into the United States. (Jeff Schmaltz MODIS Land Rapid Response Team, NASA GSFC)

The fires in the NTW are “in line with climate trends of more fires burning in the northern reaches of the globe,” according to Climate Central, an independant organization of climate scientists and journalists. A 2014 report by the Intergovernmental Panel on Climate Change, a United Nations committee, predicted that wildfire activity would double with every 1.8-Fahrenheit-degree (2-degree-Celsius) rise in average global temperatures. Such fires contribute to global warming by releasing soot, which darkens Arctic ice, promoting melting, and by adding more carbon dioxide to the atmosphere. Nearly all scientists think that the release of carbon dioxide and other greenhouse gasses into the atmosphere have significantly contributed to the rise in average atmospheric temperatures since the mid-1700′s. Forests in the NWT are part of the taiga, also called the boreal forest, a vast evergreen forest that circles the Northern Hemisphere. The taiga holds an estimate 30 percent of all the world’s carbon stored on land.

Additional World Book articles:

• Weather (2013) (a Back in Time article)
• Parched Earth (a Special Report)
• Weathering the Storm: Adapting to Global Warming (a Special Report)

May 13, 2014

A huge area of the West Antarctic Ice Sheet appears to have begun a gradual but “unstoppable” slide into the sea, according to two new studies. The findings are the first firm evidence that this section of the ice sheet, which currently poses the largest threat of rapid sea-level rise, is in an “irreversible decline.” The loss of ice there, scientists have warned, is the first step in a chain reaction that could contribute significantly to higher-than-predicted global sea levels over centuries. Moreover, said scientists involved in the research, the simulanteous retreat (shrinking) of ice over such a large area suggests that the process was triggered by a common cause, which they link, in part, to global warming.

The first study, by scientists from the University of California, Irvine, and NASA’s Jet Propulsion Laboratory, is based on 40 years of observations of six glaciers bordering the Amundsen Sea. Since 1973, the amount of ice released by the glaciers has risen 77 percent annually, an amount nearly equal to the ice entering the ocean each year from the entire Greenland Ice Sheet. The leading edges of these glaciers, called tongues or ice shelves, float on seawater. The point where a glacier loses contact with the underlying terrain and begins to float is called the grounding line. Nearly all the melting takes place on the underside of a glacier beyond this line, where the ice comes into contact with warm seawater.

The scientists found that the speed of the Amundsen Sea glaciers flowing downhill from the center of the ice sheet has increased over the past 40 years. In addition, the glaciers’ grounding lines have been retreating. This means that sections of the glaciers are now floating above places they used to touch. The grounding line for the Pine Island Glacier, for example, retreated by 19 miles (31 kilometers) between 1992 and 2011.

The second study involved advanced computer modeling of the Thwaites Glacier, one of the six glaciers in the NASA study. Scientists had thought this glacier would remain stable for thousands of years. However, said glaciologist Ian Joughin of the University of Washington, Seattle, “this glacier is really in the early stages of collapse.” Its grounding line retreated by nearly 9 miles (14 kilometers) from 1992 to 2011.

Glaciers in the NASA study appear in red. The darker the color, the faster the speed at which the glaciers are flowing toward the Admundsen Sea. (Image credit: Eric Rignot)

The retreat of a grounding line could be the first step in a chain reaction. In this process, as the line retreats, the glacier gets thinner. As the ice grows thinner, it offers less resistance to the water and flows faster. The glacier also loses its ability to hold back inland glaciers flowing toward the sea. These glaciers, in turn, grow thinner and flow faster. The result is more ice flowing into the sea and rising sea levels.

Scientists are still uncertain about the timeline for the collapse of the Amundsen Sea glaciers. The NASA scientists estimated that it could take as few as 200 or as many as 900 years for all the ice in the glaciers to melt. That meltwater would be enough to raise all sea levels by 4 feet (1.2 meters). According to a recent report by the United Nations Intergovernmental Panel on Climate Change, sea levels are projected to rise from 1 to 3 feet (26 to 98 centimeters) by 2100. However, most projections of sea-level rise do not take into account ice loss from West Antarctica. The findings from the new studies, the NASA scientists say, suggest that these projections should be revised upward.

Additional World Book articles:

• Antarctica: The Hidden Continent (a Special Report)
• Meltdown: Climate Change in the Arctic (a Special Report)
• The Great Meltdown (a Special Report)

May 9, 2014

The biggest glacier (by size) in Europe is now draining into the Barents Sea at a rate 10 times as fast as it was just a few years ago, according to data collected by a new Earth-observation satellite. The glacier, the Austfonna icecap on Svalbard, had been relatively stable for some decades. (Icecaps are glaciers that cover an area of 19,300 square miles (50,000 square kilometers) or less. Larger glaciers are called ice sheets.) Svalbard is a group of islands in the Arctic Ocean, about midway between Norway and the North Pole. The Earth-observation satellite is the Sentinel-1A, an advanced radar satellite launched last month by the European Space Agency. Scientists with the Sentinel project described the change in the icecap’s speed as “extraordinary.” At this point, they are not certain whether the speed-up is the result of natural changes in the movement of the icecap or a sign of global warming in the Arctic.

The Austfonna icecap covers more than 3,000 square miles (8,000 square kilometers) of Nordaustlandet, the second-largest island in the Svalbard archipelago. Ice from the glacier drains into the sea mainly though a so-called outlet glacier along the southeastern coast of the island. An outlet glacier is a section of an icecap or ice sheet that moves faster than the ice around it.

The chief outlet glacier of the Austfonna icecap (shown in box) is flowing into the sea at least 10 times as fast as it was only a few years ago. (ESA/DLR/Gamma/University of Leeds/University of Edinburgh)

The melting of land-based glaciers is one of the two main causes of the 8-inch (210-millimeter) average rise in global sea levels that occurred between 1880 and 2009.  The other major cause is thermal expansion caused by the warming of the oceans (water expands as it warms). According to one expert involved with the project, icecaps and glaciers contain only 1 percent of the world’s ice. But they have contributed about 50 percent of modern sea-level rise due to ice melting. Glaciers flow slowly under the influence of gravity. If the amount of new snow that accummulates on the glacier is about the same as the amount of the glacier’s ice melting into the sea, the glacier is considered stable.

Additional World Book articles:

• Ice formation
• The Great Meltdown (a Special Report)