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Pushing the Boundaries of Life: Mid-latitudes

The myriad creatures and plants with whom we share this planet are intimately tied to their habitat and zone of temperature, precipitation or ocean current. As mean temperatures rise, and climate is affected, living things have no choice but to react -- to move or adapt. On earlier pages, this Web site documents some of these changes in polar regions, where climate change is very dramatic
The same changes are at play in the mid latitudes, also. It is very clear that huge changes in biodiversity and individual creatures are happening now -- and many are accelerating.

In the past few years, scientists have published a large number of studies showing strong correlations between climate change and animal and plant range changes. The latest of these were published in the IPCC reports of 2007, based on peer-reviewed journal studies going back to January 2003 and 2004 in the journal Nature.
In one of the largest of these far-reaching peer-reviewed articles, an international group of scientists has predicted that by mid century up to a third of land plants and animal species may be pushed close to extinction. The study, "Extinction risk from climate change," measured the responses to current change and habitat limits of 1103 species in many habitats, and found that climate change is "...likely to be the greatest threat in many if not most regions." The scientists wrote that these climate effects and the damage being caused by over-grazing, over-fishing, and over-use of the planet are “strengthening the hypothesis that the natural world is experiencing the sixth major extinction event in its history.”
Nature also published an analysis of studies of more than 1,700 species indicating significant range shifts averaging 6.1 km per decade towards the poles. It reported that natural springtime events are occurring earlier by 2.3 days per decade in the late 20th century. A second analysis of 143 studies shows a significant impact of global warming is already discernible in animal and plant populations.
The IPCC review of changes to ecosystems and human habitations (see this website, section "About Global Warming") looked at over 650 studies of changes to the Earth and its inhabitants, which included 29,436 sets of long-term observations. They confirmed that effects of temperature increases are pervasive across the globe and that, in the words of Cynthia Rosenzweig, a NASA scientist who took part, “the changes have intensified.” They tallied ongoing habitat changes, landscape alterations, and loss of
biodiversity on every continent.

As changes proceed, many species will be able to shift their range or alter their behavior in response, and that is already leading to shifts in diseases, loss of agricultural production, and ecosystem alterations that affect human life. But some, perhaps many, species will be blocked because they’ve run out of mountain or island, because potentially suitable habitat has been destroyed, or because they can’t move fast enough. What will become of the familiar habitat associations of Earth or the biodiversity and genetic flexibility they contain?
Unfortunately, ecosystems are unlikely to stay intact. “Communities of species do not move together,”according to conservation biologist Thomas Lovejoy. “[Species] move individually at different rates and in different directions.” As climate change intensifies, the life zones and ecological associations familiar to us from introductory biology courses, represented by multicolored bands splashed across world maps, are not going to move in synchrony. Rather, they will deform unevenly as
the plants and animals within them react in varying ways. No less than the ice shelves of Antarctica and the permafrost of the Arctic, ecosystems worldwide are rending and disintegrating. With this, the rich biodiversity of Earth, the flow of life that humans rely on, is threatened.

See my Reference section for details of some of these studies. Also Chapter 3 of Earth Under Fire has much more detail and a description of changes occurring in national parks and protected areas. Photos of some plant and animal reactions in the temperate zone are the subject of this portion of World View of Global Warming..


Alpine meadow and fell-field ecosystems are changing under atmospheric warming. On this site at 3000 meters in the Austrian Alps, Botanist Harald Pauli and researchers are finding plant species increasing and decreasing at different rates over a 10 year period. Essentially, the familiar alpine wildflower fields are being fragmented and rearranged. This is especially dangerous for plants forced to move upwards where there is just rock and ice, says Pauli. "We are running into a really serious loss of biodiversity." The 380 sites here were established in 1994 by Georg Grabherr, Pauli and others at the University of Vienna. This alpine research idea has expanded world wide into GLORIA - the "Global Observation Research Initiative in Alpine Environments." The glaciers behind the scientists are an even more visible sign of global


Marine Biologist Rafe Sagarin points out some of the tide pool habitat that was found to have changed when he re-inventoried a 60-year-old study at Hopkins Marine Laboratory, Monterey California. Summer sea temperature has risen more than one degree in that time, and the re-survey showed many warm water tidepool animals had increased while those favoring colder water had decreased.
This nudibranch Hopkinsia rosea, discovered at and named for the Hopkins Lab, was numerous in the 1930s survey but not seen at all 60 years later. It is still found in other locations near Monterey, favoring cooler water. Other species, such as predatory snails and anemones showed great shifts in those thriving in warmer water south on the California coast.

Biologist Camille Parmesan compared old records of the Edith’s checkerspot butterfly against current habitat from Mexico to Canada and found that the insect had moved its habitat slightly north in response to climate warming. She found the level of population extinctions is four times as high at the far southern end of the range (Mexico) than at the northern. This change in a sensitive insect was predicted from the twentieth century warming of about 1 degree F.

The butterfly pictured is laying eggs on Collinsia, an annual plant of Sierra Nevada high meadows. Annual plants are more affected by weather shifts, and this is one of the factors in the butterfly population shifting as climate changes the habitat of both animals and their host plants.

Dr. Parmesan later collaborated with many European biologists and lepidopterists to show that 2/3 of butterfly species with long observational records had shifted northward by from 22 to 150 miles, consistent with temperature increases in Europe. No butterflies were found to have shifted to the south. Parmesan has found many locations in Southern France with apparently intact food-plant habitat that no longer have well known butterflies like the Apollo (Parnassius apollo)..

Throughout the temperate zone, changes are being recorded in where and when plants bloom and thrive. One recent study by botanists at the Smithsonian's National Museum of Natural History reviewed records on the spring bloom time of 100 common Washington D.C. area plants. Eighty-nine of the 100 showed significantly earlier blooming. This one, the common lawn weed deadnettle, photographed at the National Arboretum, is blooming an average of 39 days earlier than in 1970.

American ornithologists are investigating climate change in several ways. Jeff Price of the American Birding Congress collects data from birders and scientists and reports changing migration and ranges for hundreds of North American species. This yellow warbler was an early migrant at Point Pelee National Park, Ontario.

Meanwhile Terry Root of Michgan University correlated regional temperatures with a 50 year record of bird arrival at Seney National Wildlife Refuge, Michigan. Comparing yearly records kept by now-retired field biologist Elizabeth Losey with current arrival times showed significantly early in-migration.

Even though the predicted range of climate warming has just begun, many ecologial responses are already clearly visible, as seen in these and other studies. Recent scientific reviews of biologial research show that strong effects are being seen in habitats from alpine meadows to coral reefs, and from the tropics to the poles.
Among the important review articles are Gian-Reto Walther et al., "Ecological responses to recent climate change." Nature 416 (28 March 2002), and Drew Harvell et al., "Climate Warming and Disease Risks for Terrestrial and Marine Biota," Science 296 (Jun 31 2002). World View of Global Warming will be documenting some of these studies in the coming months.

Tree swallow Tachycineta bicolor in nest hole at Point Pelee, Ontario
Another study showed the egg laying date of North American tree swallows advanced by up to nine days during the period from 1959 to 1991. Reported in 1999 by Peter O. Dunn, Univ. of Wisconsin and David W. Winkler, Cornell Univ, the research correlated 3450 nest records, taking into account differences of location, elevation and other breeding factors. "WE conclude," wrote the scientists, "that tree swallows across North America are breeding earlier and that the most likely cause is a long term increase in spring temperature."

Mountains are undergoing some of the most crucial changes due to global warming. Besides the loss of glaciers, warming temperatures are driving the alpine zones farther up toward the summits. Eventually, the highest alpine plants and animals will have nowhere to go. This effect is being seen in and near Rocky Mountain National Park, where marmots are coming out of hibernation earlier, and in Great Basin mountains where some populations of pikas have disappeared apparently due to climate changes.

Other research is focused on alpine trees and meadows, showing that mountain hemlocks and sub alpine firs are moving into meadow areas in Mt Rainier and Olympic National Parks -- and the effect is expected to accelerate if temperatures continue to rise rapidly. In Yellowstone National Park, the zone of life for the whitebark pine is moving up toward the summit of the mountains. If this reduces the number of these pines, it will affect not merely scenery, because the seeds of the whitebark are a crucial part of grizzly bear diet.

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U.S. Global Change Research Program summarizes climate changes in the United States in a
June 2008 report.
This report, "Global Climate Change Impacts in the United States," spells out in great detail what global warming has already caused across the continental states (Alaska and Hawaii are of course included, and show how these American states are affected by important shifts in Arctic and Pacific island climates). The report is available at the government climate website.
The summary here is taken directly from the report and should dispel any doubt that the U.S. has already been changed by increasing atmospheric temperatures. The nation has a huge stake in lives, buildings, agriculture and ecosystems being damaged enormously if heat-trapping greenhouse gases are not curtailed very rapidly -- here and around the world.
1. Global warming is unequivocal and primarily human-induced.
Global temperature has increased over the past 50 years. U.S. average temperature has risen more than 2 degrees F over the past 50 years. This observed increase is due primarily to human-induced
emissions of heat-trapping gases.
2. Climate changes are underway in the United States and are projected to grow.
Climate-related changes are already observed in the United States and its coastal waters. These include increases in heavy downpours, rising temperature and sea level, rapidly retreating glaciers, thawing permafrost, lengthening growing seasons, lengthening ice-free seasons in the ocean and on lakes and rivers, earlier snowmelt, and alterations in river flows. These changes are projected to grow.
3. Widespread climate-related impacts are occurring now and are expected to increase.
Climate changes are already affecting water, energy, transportation, agriculture, ecosystems, and health. These impacts are different from region to region and will grow under projected climate change.
4. Climate change will stress water resources.
Water is an issue in every region, but the nature of the potential impacts varies. Drought, related to reduced precipitation, increased evaporation, and increased water loss from plants, is an important issue in many regions, especially in the West. Floods and water quality problems are likely to be amplified by climate change in most regions. Declines in mountain snowpack are important in the West and Alaska where snowpack provides vital natural water storage.
5. Crop and livestock production will be increasingly challenged.
Many crops show positive responses to elevated carbon dioxide and low levels of warming, but higher levels of warming often negatively affect growth and yields. Increased pests, water stress, diseases, and weather extremes will pose adaptation challenges for crop and livestock production.
6. Coastal areas are at increasing risk from sea-level rise and storm surge.
Sea-level rise and storm surge place many U.S. coastal areas at increasing risk of erosion and flooding, especially along the Atlantic and Gulf Coasts, Pacific Islands, and parts of Alaska. Energy and transportation infrastructure and other property in coastal areas are very likely to be adversely affected.
7. Risks to human health will increase.
Harmful health impacts of climate change are related to increasing heat stress, waterborne diseases, poor air quality, extreme weather events, and diseases transmitted by insects and rodents. Reduced cold stress provides some benefits. Robust public health infrastructure can reduce the potential for negative impacts.
8. Climate change will interact with many social and environmental stresses.
Climate change will combine with pollution, population growth, overuse of resources, urbanization, and other social, economic, and environmental stresses to create larger impacts than from any of these factors alone.
9. Thresholds will be crossed, leading to large changes in climate and ecosystems.
There are a variety of thresholds in the climate system and ecosystems. These thresholds determine, for example, the presence of sea ice and permafrost, and the survival of species, from fish to insect pests, with implications for society. With further climate change, the crossing of additional thresholds is expected.
10. Future climate change and its impacts depend on choices made today.
The amount and rate of future climate change depend primarily on current and future human-caused emissions of heat-trapping gases and airborne particles. Responses involve reducing emissions to limit future warming, and adapting to the changes that are unavoidable

Hello.. I'm Rozita.

Pushing the Boundaries of Life: Tropics
For many years, it was thought that tropical rainforests were essentially unaffected by climate change Now studies are showing that not only were they changed during past events like ice ages, but some areas are being affected right now by warming. At Monteverde Cloud Forest Reserve, Costa Rica, clouds are forming higher, drying out some of the habitat and causing changes in flora and fauna.

The most celebrated peer reviewed case is the disappearance of the golden toads, Bufo periglenes. Each year Dr. Alan Pounds and others search for the distinctive orange amphibian in its restricted habitat along a narrow, fog-bound ridge. About 1500 toads were sighted in 1987. But now the breeding pools remain empty -- the toad has not been seen since 1991 and is feared extinct.

The golden toad and other amphibians and lizards studied by Dr. Pounds are in decline apparently due to regional temperature increases lifting the level of clouds, effectively drying out the cloud forest moisture on which they depend. This species, Antelopus varius, once common throughout Costa Rica, was not found at all in a recent survey, according to Dr. Pounds. Some of this change may be due to deforestation in lowland Costa Rica, and a group of scientists at Monteverde is planning more study. At the same time, research by Dr. Nalini Nadkarni shows drying will drastically change the composition of the diverse epiphyte community that inhabits the cloud forest canopy.

Dryer conditions in the cloud forest concern Dr. Karen Masters, who studies tiny Pleurothallic canopy orchids. Lenghtening dry periods could drive some into extinction. "We are now seeing 2, 3 even 5 days in a row without moisture." she reports. "This is very challenging to these orchids." Also, recent repeat surveys of bats by Dr. Richard LaVal, and of birds by Debra DeRosier (repeating a 1979 survey by Dr. George Powell) shows lowland, dry habitat species are already moving higher into former cloud forest areas.


Other big changes are being monitored in the tropics, too. Sixteen years of data on tree growth, tropical air temperatures and CO2 readings indicate that a warming climate may cause the tropical forests to give off more carbon dioxide than they take up. This wouldupset the common belief that tropical forests are always a sink for carbon, taking huge amounts out of the atmosphere.
The study, by Deborah and David Clark of the La Selva biological station in Costa Rica, and Charles Keeling and Stephen Piper of the Scripps Institution, reports that rainforest trees grow much more slowly in warmer nighttime
In other parts of the tropics, even in places that have been undisturbed for more than 4500 years, the rise in atmospheric CO2 appears to be changing the composition of the forest. In a paper in the 11 March 2004 issue of Nature, William Laurance and colleagues document that many tree genera in Amazonia are growing faster than they were in the 1980s.
Other tree types are declining in vitality. The study of 13,700 trees in 18 very isolated plots in Brazil concluded that increased carbon dioxide is the most plausible explanation for the abrupt shifts in species growth. This "could also have serious ecological repercussions for the diverse Amazonian biota" wrote the scientists.

Warming Winds, Rising Tides: Oceans

Coral reefs are probably the most complex ecosystems on the planet, home to hundreds of thousands of species. They protect and support the lives of millions of people around the tropical zones, and are a font of wealth from fishing and recreation. The damage being caused to reefs by warming seas is one of the most serious effects of global warming.

Rising sea temperature coupled with the strong El Nino of 1998 was devastating to much of the world's coral reefs. High water temperatures caused coral bleaching and subsequent death or adverse change to sixteen percent of world reefs overall and up to 46 percent in parts of the Indian Ocean.

Temperatures beyond norms causes coral to expel the microscopic symbionts, zooxanthellae, that also give them color. If this bleaching continues for days to weeks, the coral dies and algae takes over the reefs, changing the ecosystem. During another bout of bleaching in 2002, the international coral reef information network ReefBase reported 430 cases of coral bleaching, most of them on the Great Barrier Reef, the world's largest.

As it takes up heat, ocean water expands -- the major cause of sea level rising at a rate now exceeding 8 inches a century. Sea level rose about 6 inches in the 20th century, but the rise is predicted to increase to as much as a meter by 2100 (see Coastlines and Glacier sections). Coral, which thrives at and near the sea surface, is not expected to be able to keep pace with this rapid increase in water depth. In addition, seas are dissolving more and more carbon dioxide. Even though this adds more carbon, a raw material for coral making calcium carbonate reefs, it also acidifies the water, actually inhibiting the growth of coral.

Coupled with damage from human activities and development, this growing danger has lead some scientists to predict the end of reefs across much of the ocean. In reports in 1999 and 2004, Australian Marine Biologist Ove Hoegh-Guldberg and others said high water temperatures and bleaching will become yearly events before mid-century. Living coral may be reduced by 95 percent on the Great Barrier Reef. Hough-Guldberg said recently, "We are damaging a large part of the world's biodiversity" on the reefs. "We're 'chopping them down' with global warming. These reefs will be so changed that we'll have to find ways to re-employ all those people," the millions who depend directly on reef fisheries and recreation. "The implications are huge."
For a current report on a Pacific Island nation that is threatened by higher sea levels, and other places that are being inundated,

Hai... I'm Norhanah.

Arctic Ocean sea ice diminishes to record low

Arctic sea ice has now surpassed all previous records for the lowest absolute minimum summer extent. The "stunning record low" of 4.13 million square kilometers was recorded by satellite images on September 16, according to the National Snow and Ice Data Center. The previous record, 5.32 million square kilometers, was measured on September 20-21, 2005.

The minimum for 2007 is smaller by 1.19 million square kilometers (460,000 square miles) than the previous low, roughly the size of Texas and California combined, or nearly five United Kingdoms. This year also saw the extended opening of the Northwest Passage through islands north of Canada for the first time.

Warming Winds, Rising Tides: Arctic
Sea level rise also affects the Arctic, where it is frequently combines with permafrost thaw to create severe erosion. The native village of Shismaref Alaska, a village of about 590 Inupiats perched on a sandy barrier island on the NW shore of Seward Peninsula, has failed to halt the rising Bering Sea. Shore erosion of the narrow spit has been severe since the 1950s, and protective armor and wire gabions have been ineffective. The town faces a decision to move inland, away from this traditional site. Townspeople voted in 2002 to move their village to higher, more protected ground away from the ocean.


On Baffin Island, across from Greenland in Nunavut, Canada, the loss of ice and permafrost is affecting daily life of native Inuits. Winter hunting and fishing is limited severely by loss of ice. In summer, permafrost is thawing, creating more erosion, and ice that once covered the surrounding mountains year long is nearly all melted. Elders in the village of Pangnirtung report that winds have shifted and winters are getting much shorter -- observations that weather records confirm.
Elisapee Ishulutaq, a 78 year old artist with a spry and radiant smile, was born in an outpost camp when most natives here were nomadic. They were dog sledding as late as July, she remembers, more than two months later than snow and ice breaks up now. "All the mountains were covered with glaciers." she said. "There isn't any deep snow anymore." Elisapee pointed to her younger self in black and white photos on her living room wall. She said there were stories in her childhood about a warmer future. "It was foretold by the elders that sometime the north would warm up and south would cool down."

Kids in Pangnirtung have taken to golf in the increasingly dry and dusty summer months. This contrasts with Elders' memories and old photographs of villagers clad in warm skins and fir in mid-summer, playing more traditional games like tug of war while around them the mountains were snowcapped
________________________________________

Hello.... I am Norhanah....I want to discuss about :


Sea level

Higher temperatures will make the water of the seas and oceans expand. Ice melting in the Antarctic and Greenland will flow into the sea.
All over the world, sea levels may rise, perhaps by as much as 20 to 40 cm, by the beginning of the next century.
Higher sea levels will threaten the low-lying coastal areas of the world, such as the Netherlands and Bangladesh. Throughout the world, millions of people and areas of land will be at danger from flooding. Many people will have to leave their homes and large areas of farmland will be ruined because of floods. In Britain, East Anglia and the Thames estuary will be at risk from the rising sea.
Farming
The changes in the weather will affect the types of crops grown in different parts of the world. Some crops, such as wheat and rice grow better in higher temperatures, but other plants, such as maize and sugarcane do not. Changes in the amount of rainfall will also affect how many plants grow.
The effect of a change in the weather on plant growth may lead to some countries not having enough food. Brazil, parts of Africa, south-east Asia and China will be affected the most and many people could suffer from hunger.

Water

Everywhere in the world, there is a big demand for water and in many regions, such as the Sahara in Africa, there is not enough water for the people. Changes in the weather will bring more rain in some countries, but others will have less rain.
In Britain, the Southeast will be at risk from drought.

IN DANGER!

Plants & Animals
It has taken million of years for life to become used to the conditions on Earth. As weather and temperature changes, the homes of plants and animals will be affected all over the world.
For example, polar bears and seals, will have to find new land for hunting and living, if the ice in the Arctic melts.
Many animals and plants may not be able to cope with these changes and could die. This could cause the loss of some animal and plant species in certain areas of the world or everywhere on Earth.

People
The changes in climate will affect everyone, but some populations will be at greater risk. For example, countries whose coastal regions have a large population, such as Egypt and China, may see whole populations move inland to avoid flood risk areas. The effect on people will depend on how well we can adapt to the changes and how much we can do to reduce climate change in the world.

Go to the next sheet on the Ozone Hole.......

Physical impacts

So now,I (Rosyati Saien)again want to discuss about the global warming ini physical impacts.

Effects on weather

Increasing temperature is likely to lead to increasing precipitation but the effects on storms are less clear. Extratropical storms partly depend on the temperature gradient, which is predicted to weaken in the northern hemisphere as the polar region warms more than the rest of the hemisphere.

Extreme weather


Global warming may be responsible in part for some trends in natural disasters such as extreme weather.
Based on future projections of climate change, the IPCC report makes a number of predictions. It is predicted that over most land areas, the frequency of warm spells/heat waves will very likely increase. It is likely that:
• Increased areas will be affected by drought
• There will be increased intense tropical cyclone activity
• There will be increased incidences of extreme high sea level (excluding tsunamis)
Storm strength leading to extreme weather is increasing, such as the power dissipation index of hurricane intensity. Kerry Emanuel writes that hurricane power dissipation is highly correlated with temperature, reflecting global warming. However, a further study by Emanuel using current model output concluded that the increase in power dissipation in recent decades cannot be completely attributed to global warming. Hurricane modeling has produced similar results, finding that hurricanes, simulated under warmer, high-CO2 conditions, are more intense, however, hurricane frequency will be reduced. Worldwide, the proportion of hurricanes reaching categories 4 or 5 – with wind speeds above 56 metres per second – has risen from 20% in the 1970s to 35% in the 1990s. Precipitation hitting the US from hurricanes has increased by 7% over the twentieth century. The extent to which this is due to global warming as opposed to the Atlantic Multidecadal Oscillation is unclear. Some studies have found that the increase in sea surface temperature may be offset by an increase in wind shear, leading to little or no change in hurricane activity. Hoyos et al. (2006) have linked the increasing trend in number of category 4 and 5 hurricanes for the period 1970-2004 directly to the trend in sea surface temperatures.
Increases in catastrophes resulting from extreme weather are mainly caused by increasing population densities, and anticipated future increases are similarly dominated by societal change rather than climate change. The World Meteorological Organization explains that “though there is evidence both for and against the existence of a detectable anthropogenic signal in the tropical cyclone climate record to date, no firm conclusion can be made on this point.” They also clarified that “no individual tropical cyclone can be directly attributed to climate change.”
Thomas Knutson and Robert E. Tuleya of NOAA stated in 2004 that warming induced by greenhouse gas may lead to increasing occurrence of highly destructive category-5 storms. In 2008, Knutson et al. found that Atlantic hurricane and tropical storm frequencies could reduce under future greenhouse-gas-induced warming. Vecchi and Soden find that wind shear, the increase of which acts to inhibit tropical cyclones, also changes in model-projections of global warming. There are projected increases of wind shear in the tropical Atlantic and East Pacific associated with the deceleration of the Walker circulation, as well as decreases of wind shear in the western and central Pacific. The study does not make claims about the net effect on Atlantic and East Pacific hurricanes of the warming and moistening atmospheres, and the model-projected increases in Atlantic wind shear.
A substantially higher risk of extreme weather does not necessarily mean a noticeably greater risk of slightly-above-average weather. However, the evidence is clear that severe weather and moderate rainfall are also increasing. Increases in temperature are expected to produce more intense convection over land and a higher frequency of the most severe storms.

Increased evaporation

Increasing water vapor at Boulder, Colorado.
Over the course of the 20th century, evaporation rates have reduced worldwide , this is thought by many to be explained by global dimming. As the climate grows warmer and the causes of global dimming are reduced, evaporation will increase due to warmer oceans. Because the world is a closed system this will cause heavier rainfall, with more erosion. This erosion, in turn, can in vulnerable tropical areas (especially in Africa) lead to desertification. On the other hand, in other areas, increased rainfall lead to growth of forests in dry desert areas.
Scientists have found evidence that increased evaporation could result in more extreme weather as global warming progresses. The IPCC Third Annual Report says: "...global average water vapor concentration and precipitation are projected to increase during the 21st century. By the second half of the 21st century, it is likely that precipitation will have increased over northern mid- to high latitudes and Antarctica in winter. At low latitudes there are both regional increases and decreases over land areas. Larger year to year variations in precipitation are very likely over most areas where an increase in mean precipitation is projected."


As the World Meteorological Organization explains, “recent increase in societal impact from tropical cyclones has largely been caused by rising concentrations of population and infrastructure in coastal regions.” Pielke et al. (2008) normalized mainland U.S. hurricane damage from 1900–2005 to 2005 values and found no remaining trend of increasing absolute damage. The 1970s and 1980s were notable because of the extremely low amounts of damage compared to other decades. The decade 1996–2005 has the second most damage among the past 11 decades, with only the decade 1926–1935 surpassing its costs. The most damaging single storm is the 1926 Miami hurricane, with $157 billion of normalized damage.

The American Insurance Journal predicted that “catastrophe losses should be expected to double roughly every 10 years because of increases in construction costs, increases in the number of structures and changes in their characteristics.” The Association of British Insurers has stated that limiting carbon emissions would avoid 80% of the projected additional annual cost of tropical cyclones by the 2080s. The cost is also increasing partly because of building in exposed areas such as coasts and floodplains. The ABI claims that reduction of the vulnerability to some inevitable effects of climate change, for example through more resilient buildings and improved flood defences, could also result in considerable cost-savings in the longterm.



The first recorded South Atlantic hurricane, "Catarina", which hit Brazil in March 2004
In the northern hemisphere, the southern part of the Arctic region (home to 4,000,000 people) has experienced a temperature rise of 1 °C to 3 °C (1.8 °F to 5.4 °F) over the last 50 years. Canada, Alaska and Russia are experiencing initial melting of permafrost. This may disrupt ecosystems and by increasing bacterial activity in the soil lead to these areas becoming carbon sources instead of carbon sinks. A study (published in Science) of changes to eastern Siberia's permafrost suggests that it is gradually disappearing in the southern regions, leading to the loss of nearly 11% of Siberia's nearly 11,000 lakes since 1971. At the same time, western Siberia is at the initial stage where melting permafrost is creating new lakes, which will eventually start disappearing as in the east. Furthermore, permafrost melting will eventually cause methane release from melting permafrost peat bogs.
Prior to March 2004, no tropical cyclone had been observed in the South Atlantic Ocean. The first Atlantic cyclone to form south of the equator hit Brazil on March 28, 2004 with 40 m/s (144 km/h) winds, although some Brazilian meteorologists deny that it was a hurricane. Monitoring systems may have to be extended 1,600 km (1,000 miles) further south. There is no agreement as to whether this hurricane is linked to climate change, but one climate model exhibits increased tropical cyclone genesis in the South Atlantic under global warming by the end of the 21st century.



A map of the change in thickness of mountain glaciers since 1970. Thinning in orange and red, thickening in blue.
In historic times, glaciers grew during a cool period from about 1550 to 1850 known as the Little Ice Age. Subsequently, until about 1940, glaciers around the world retreated as the climate warmed. Glacier retreat declined and reversed in many cases from 1950 to 1980 as a slight global cooling occurred. Since 1980, glacier retreat has become increasingly rapid and ubiquitous, and has threatened the existence of many of the glaciers of the world. This process has increased markedly since 1995.
Excluding the ice caps and ice sheets of the Arctic and Antarctic, the total surface area of glaciers worldwide has decreased by 50% since the end of the 19th century. Currently glacier retreat rates and mass balance losses have been increasing in the Andes, Alps, Pyrenees, Himalayas, Rocky Mountains and North Cascades.
The loss of glaciers not only directly causes landslides, flash floods and glacial lake overflow, but also increases annual variation in water flows in rivers. Glacier runoff declines in the summer as glaciers decrease in size, this decline is already observable in several regions.[44] Glaciers retain water on mountains in high precipitation years, since the snow cover accumulating on glaciers protects the ice from melting. In warmer and drier years, glaciers offset the lower precipitation amounts with a higher meltwater input.
Of particular importance are the Hindu Kush and Himalayan glacial melts that comprise the principal dry-season water source of many of the major rivers of the Central, South, East and Southeast Asian mainland. Increased melting would cause greater flow for several decades, after which "some areas of the most populated regions on Earth are likely to 'run out of water'" as source glaciers are depleted. The Tibetan Plateau contains the world's third-largest store of ice. Temperatures there are rising four times faster than in the rest of China, and glacial retreat is at a high speed compared to elsewhere in the world.
According to a UN climate report, the Himalayan glaciers that are the sources of Asia's biggest rivers—Ganges, Indus, Brahmaputra, Yangtze, Mekong, Salween and Yellow—could disappear by 2035 as temperatures rise. Approximately 2.4 billion people live in the drainage basin of the Himalayan rivers. India, China, Pakistan, Bangladesh, Nepal and Myanmar could experience floods followed by droughts in coming decades. In India alone, the Ganges provides water for drinking and farming for more than 500 million people. It has to be acknowledged, however, that increased seasonal runoff of Himalayan glaciers led to increased agricultural production in northern India throughout the 20th century.

The recession of mountain glaciers, notably in Western North America, Franz-Josef Land, Asia, the Alps, the Pyrenees, Indonesia and Africa, and tropical and sub-tropical regions of South America, has been used to provide qualitative support to the rise in global temperatures since the late 19th century. Many glaciers are being lost to melting further raising concerns about future local water resources in these glaciated areas. In Western North America the 47 North Cascade glaciers observed all are retreating.

Retreat of the Helheim Glacier, Greenland
Despite their proximity and importance to human populations, the mountain and valley glaciers of temperate latitudes amount to a small fraction of glacial ice on the earth. About 99% is in the great ice sheets of polar and subpolar Antarctica and Greenland. These continuous continental-scale ice sheets, 3 kilometres (1.9 mi) or more in thickness, cap the polar and subpolar land masses. Like rivers flowing from an enormous lake, numerous outlet glaciers transport ice from the margins of the ice sheet to the ocean.
Glacier retreat has been observed in these outlet glaciers, resulting in an increase of the ice flow rate. In Greenland the period since the year 2000 has brought retreat to several very large glaciers that had long been stable. Three glaciers that have been researched, Helheim, Jakobshavn Isbræ and Kangerdlugssuaq Glaciers, jointly drain more than 16% of the Greenland Ice Sheet. Satellite images and aerial photographs from the 1950s and 1970s show that the front of the glacier had remained in the same place for decades. But in 2001 it began retreating rapidly, retreating 7.2 km (4.5 mi) between 2001 and 2005. It has also accelerated from 20 m (66 ft)/day to 32 m (100 ft)/day. Jakobshavn Isbræ in western Greenland had been moving at speeds of over 24 m (79 ft)/day with a stable terminus since at least 1950. The glacier's ice tongue began to break apart in 2000, leading to almost complete disintegration in 2003, while the retreat rate doubled to over 30 m (98 ft)/day.
Oceans
The role of the oceans in global warming is a complex one. The oceans serve as a sink for carbon dioxide, taking up much that would otherwise remain in the atmosphere, but increased levels of CO2 have led to ocean acidification. Furthermore, as the temperature of the oceans increases, they become less able to absorb excess CO2. Global warming is projected to have a number of effects on the oceans. Ongoing effects include rising sea levels due to thermal expansion and melting of glaciers and ice sheets, and warming of the ocean surface, leading to increased temperature stratification. Other possible effects include large-scale changes in ocean circulation.

Sea level rise

Sea level has been rising 0.2 cm/year, based on measurements of sea level rise from 23 long tide gauge records in geologically stable environments.
With increasing average global temperature, the water in the oceans expands in volume, and additional water enters them which had previously been locked up on land in glaciers, for example, the Greenland and the Antarctic ice sheets. For most glaciers worldwide, an average volume loss of 60% until 2050 is predicted. Meanwhile, the estimated total ice melting rate over Greenland is 239 ± 23 cubic kilometres (57 ± 5.5 cu mi) per year, mostly from East Greenland. The Antarctic ice sheet, however, is expected to grow during the 21st century because of increased precipitation. Under the IPCC Special Report on Emission Scenario (SRES) A1B, by the mid-2090s global sea level will reach 0.22 to 0.44 m (8.7 to 17 in) above 1990 levels, and is currently rising at about 4 mm (0.16 in) per year. Since 1900, the sea level has risen at an average of 1.7 mm (0.067 in) per year; since 1993, satellite altimetry from TOPEX/Poseidon indicates a rate of about 3 mm (0.12 in) per year.
The sea level has risen more than 120 metres (390 ft) since the Last Glacial Maximum about 20,000 years ago. The bulk of that occurred before 7000 years ago. Global temperature declined after the Holocene Climatic Optimum, causing a sea level lowering of 0.7 ± 0.1 m (28 ± 3.9 in) between 4000 and 2500 years before present. From 3000 years ago to the start of the 19th century, sea level was almost constant, with only minor fluctuations. However, the Medieval Warm Period may have caused some sea level rise; evidence has been found in the Pacific Ocean for a rise to perhaps 0.9 m (2 ft 11 in) above present level in 700 BP.
In a paper published in 2007, the climatologist James Hansen et al. claimed that ice at the poles does not melt in a gradual and linear fashion, but that another according to the geological record, the ice sheets can suddenly destabilize when a certain threshold is exceeded. In this paper Hansen et al. state:
Our concern that BAU GHG scenarios would cause large sealevel rise this century (Hansen 2005) differs from estimates of IPCC (2001, 2007), which foresees little or no contribution to twentyfirst century sealevel rise from Greenland and Antarctica. However, the IPCC analyses and projections do not well account for the nonlinear physics of wet ice sheet disintegration, ice streams and eroding ice shelves, nor are they consistent with the palaeoclimate evidence we have presented for the absence of discernible lag between ice sheet forcing and sealevel rise.[62]
Sea level rise due to the collapse of an ice sheet would be distributed nonuniformly across the globe. The loss of mass in the region around the ice sheet would decrease the gravitational potential there, reducing the amount of local sea level rise or even causing local sea level fall. The loss of the localized mass would also change the moment of inertia of the Earth, as flow in the Earth's mantle will require 10-15 thousand years to make up the mass deficit. This change in the moment of inertia results in true polar wander, in which the Earth's rotational axis remains fixed with respect to the sun, but the rigid sphere of the Earth rotates with respect to it. This changes the location of the equatorial bulge of the Earth and further affects the geoid, or global potential field. A 2009 study of the effects of collapse of the West Antarctic Ice Sheet shows the result of both of these effects. Instead of a global 5-meter sea level rise, western Antarctica would experience approximately 25 centimeters of sea level fall, while the United States, parts of Canada, and the Indian Ocean, would experience up to 6.5 meters of sea level rise.
A paper published in 2008 by a group of researchers at the University of Wisconsin lead by Anders Carlson used the deglaciation of North America at 9000 years before present as an analogue to predict sea level rise of 1.3 meters in the next century, which is also much higher than the IPCC predictions. However, models of glacial flow in the smaller present-day ice sheets show that a probable maximum value for sea level rise in the next century is 80 centimeters, based on limitations on how quickly ice can flow below the equilibrium line altitude and to the sea.

Temperature rise

From 1961 to 2003, the global ocean temperature has risen by 0.10 °C from the surface to a depth of 700 m. There is variability both year-to-year and over longer time scales, with global ocean heat content observations showing high rates of warming for 1991 to 2003, but some cooling from 2003 to 2007. The temperature of the Antarctic Southern Ocean rose by 0.17 °C (0.31 °F) between the 1950s and the 1980s, nearly twice the rate for the world's oceans as a whole [67]. As well as having effects on ecosystems (e.g. by melting sea ice, affecting algae that grow on its underside), warming reduces the ocean's ability to absorb CO2

Ocean acidification

Ocean acidification is an effect of rising concentrations of CO2 in the atmosphere, and is not a direct consequence of global warming. The oceans soak up much of the CO2 produced by living organisms, either as dissolved gas, or in the skeletons of tiny marine creatures that fall to the bottom to become chalk or limestone. Oceans currently absorb about one tonne of CO2 per person per year. It is estimated that the oceans have absorbed around half of all CO2 generated by human activities since 1800 (118 ± 19 petagrams of carbon from 1800 to 1994). In water, CO2 becomes a weak carbonic acid, and the increase in the greenhouse gas since the Industrial Revolution has already lowered the average pH (the laboratory measure of acidity) of seawater by 0.1 units, to 8.2. Predicted emissions could lower the pH by a further 0.5 by 2100, to a level probably not seen for hundreds of millennia and, critically, at a rate of change probably 100 times greater than at any time over this period.
There are concerns that increasing acidification could have a particularly detrimental effect on corals (16% of the world's coral reefs have died from bleaching caused by warm water in 1998, which coincidentally was the warmest year ever recorded) and other marine organisms with calcium carbonate shells.
Shutdown of thermohaline circulation
Main article: Shutdown of thermohaline circulation
There is some speculation that global warming could, via a shutdown or slowdown of the thermohaline circulation, trigger localized cooling in the North Atlantic and lead to cooling, or lesser warming, in that region.This would affect in particular areas like Scandinavia and Britain that are warmed by the North Atlantic drift.
The chances of this near-term collapse of the circulation are unclear; there is some evidence for the short-term stability of the Gulf Stream and possible weakening of the North Atlantic drift.However, the degree of weakening, and whether it will be sufficient to shut down the circulation, is under debate. As yet, no cooling has been found in northern Europe or nearby seas.Lenton et al. found that "simulations clearly pass a THC tipping point this century".

Oxygen depletion

The amount of oxygen dissolved in the oceans may decline, with adverse consequences for ocean life.

Effects of global warming

Hi,friend.I`m Rosyati.I want to share with you about the effects of the global warming.My friend already talking about it,but this is my opinion on it.
The effects of global warming and climate change are of concern both for the environment and human life. Evidence of observed climate change includes the instrumental temperature record, rising sea levels, and decreased snow cover in the Northern Hemisphere. According to the IPCC Fourth Assessment Report, "[most] of the observed increase in global average temperatures since the mid-20th century is very likely due to the observed increase in [human greenhouse gas] concentrations". It is predicted that future climate changes will include further global warming (i.e., an upward trend in global mean temperature), sea level rise, and a probable increase in the frequency of some extreme weather events. Ecosystems are seen as being particularly vulnerable to climate change. Human systems are seen as being variable in their capacity to adapt to future climate change. To reduce the risk of large changes in future climate, many countries have implemented policies designed to reduce their emissions of greenhouse gases.See you next time ok.