Scientists have a good understanding of what has changed earth’s climate in the past: Incoming solar radiation is the main climate driver. Its energy output increased about 0.1% from 1750 to 1950, increasing temperatures by 0.2°F (0.1°C) in the first part of the 20th century. But since 1979, when we began taking measurements from space, the data show no long-term change in total solar energy, even though Earth has been warming. Repetitive cycles in Earth’s orbit that occur over tens of thousands of years can influence the angle and timing of sunlight. In the distant past, drifting continents make a big difference in climate over millions of years by changing ice caps at the poles and by altering ocean currents, which transport heat and cold throughout the ocean depths. Huge volcanic eruptions can cool Earth by injecting ash and tiny particles into the stratosphere. Changes in the concentration of greenhouse gases, which occur both naturally and as a result of human activities, also influence Earth’s climate.
Global Climatic Change.
Climate Change:Fitting the pieces together Presented by: M Anirudh Srinivas Arjun Krishnan Sailesh Krishna K C
Introduction • What is climate change? • Climate change refers to any significant change in the measures of climate lasting for an extended period of time. In other words, climate change includes major changes in temperature, precipitation, or wind patterns, among other effects, that occur over several decades or longer.
• What is global warming?• Global warming refers to the recent and ongoing rise in global average temperature near Earths surface. It is caused mostly by increasing concentrations of greenhouse gases in the atmosphere. Global warming is causing climate patterns to change. However, global warming itself represents only one aspect of climate change.
History of Climate Change • 1972 - first UN environment conference, in Stockholm. • 1975 - human population reaches four billion. • 1975 - US scientist Wallace Broecker puts the term "global warming" into the public domain in the title of a scientific paper. • 1987 - human population reaches five billion • 1987 - Montreal Protocol agreed, restricting chemicals that damage the ozone layer. Although not established with climate change in mind, it has had a greater impact on greenhouse gas emissions than the Kyoto Protocol. • 1988 - Intergovernmental Panel on Climate Change (IPCC) formed. • 1989 - UK Prime Minister Margaret Thatcher warns in a speech to the UN about the amount of CO2 in the atmosphere. She calls for a global treaty on climate change. • 1989 - carbon emissions from fossil fuel burning and industry reach six billion tons per year.
History of Climate Change • 1990 - IPCC produces First Assessment Report. It concludes that temperatures have risen by 0.3-0.6C over the last century, that humanitys emissions are adding to the atmospheres natural complement of greenhouse gases, and that the addition would be expected to result in warming. • 1992 - at the Earth Summit in Rio de Janeiro, governments agree the United Framework Convention on Climate Change. Its key objective is "stabilization of greenhouse gas concentrations in the atmosphere at a level that would prevent dangerous anthropogenic interference with the climate system". • 1995 - IPCC Second Assessment Report concludes that the balance of evidence suggests "a discernible human influence" on the Earths climate. This was the first statement that held humans responsible for climate change. • 1997 - Kyoto Protocol agreed. Developed nations (apart from the US) pledge to reduce emissions by an average of 5% by the period 2008-2012. • 1998 - strong El Nino conditions combine with global warming to produce the warmest year on record. The average global temperature reached 0.52C above the mean for the period 1961-1990.
History of Climate Change • 1999 - human population reaches six billion. • 2001 - IPCC Third Assessment Report finds "new and stronger evidence" that humanitys emissions of greenhouse gases are the main cause of the warming seen in the second half of the 20th Century. • 2005 - the Kyoto Protocol becomes international law for those countries still inside it. • 2005 - UK Prime Minister Tony Blair selects climate change as a priority for his terms as chair of the G8 and president of the EU. • 2006 - the Stern Review concludes that climate change could damage global GDP by up to 20% if left unchecked - but curbing it would cost about 1% of global GDP. • 2006 - carbon emissions from fossil fuel burning and industry reach eight billion tonnes per year. • 2007 - the IPCCs Fourth Assessment Report concludes it is more than 90% likely that humanitys emissions of greenhouse gases are responsible for modern-day climate change.
History of Climate Change • 2007 - the IPCC and former US vice-president Al Gore receive the Nobel Peace Prize "for their efforts to build up and disseminate greater knowledge about man-made climate change, and to lay the foundations for the measures that are needed to counteract such change". • 2007 - at UN negotiations in Bali, governments agree the two-year "Bali roadmap" aimed at hammering out a new global treaty by the end of 2009. • 2008 - CO2 rises from 315 parts per million (ppm) in 1958 to 380ppm in 2008. • 2008 - two months before taking office, incoming US president Barrack Obama pledges to "engage vigorously" with the rest of the world on climate change. • 2009 - China overtakes the US as the worlds biggest greenhouse gas emitter - although the US remains well ahead on a per-capita basis. • 2009 - 192 governments convene for the UN climate summit in Copenhagen.
Population Increase • Increased population in under-developed countries is causing a hindrance to the world enhancement standards as these Third World countries begin to use greater amounts of energy and the problem of global warming expands.
Deforestation • The use of forests for fuel (wood and charcoal) is one cause of deforestation • In the first world, the appetite for wood and paper products, the consumption of livestock grazed on former forest land, and the use of tropical forest lands for commodities like plantations contributes to the mass deforestation of our world. • Forests remove and store carbon dioxide from the atmosphere, and this deforestation releases large amounts of carbon.
The Big One • And then, the major cause of global warming…
Greenhouse Gases Carbon dioxide Nitrous oxide Methane Water Water
Carbon dioxide • Carbon dioxide is the primary greenhouse gas that contributes to climate change. • CO2 is absorbed and emitted naturally as part of the carbon cycle, through animal and plant respiration, volcanic eruptions, and ocean- atmosphere exchange. • Human activities, such as the burning of fossil fuels and changes in land use, release large amounts of carbon to the atmosphere, causing CO2 concentrations in the atmosphere to rise.
Methane • Methane is another potent greenhouse gas. When organic matter is broken down by bacteria under anaerobic conditions as in rice paddies, methane is produced. • The process also takes place in the intestines of herbivorous animals, and with the increase in the amount of concentrated livestock production, the level of methane released into the atmosphere is increasing. • Another source of methane is methane clathrate, a compound containing large amounts of methane trapped in the crystal structure of ice. As methane escapes from the Arctic seabed, the rate of global warming will increase significantly.
Nitrous Oxide • In the last half of the 20th century, the use of chemical fertilizers has risen dramatically. • The high rate of application of nitrogen-rich fertilizers has effects on the heat storage of cropland (nitrogen oxides have 300 times more heat-trapping capacity per unit of volume than carbon dioxide) and the run-off of excess fertilizers creates ‘dead-zones’ in our oceans. • In addition to these effects, high nitrate levels in groundwater due to over-fertilization are cause for concern for human health.
Keeping Our Planet Warm • The greenhouse effect is a process caused by greenhouse gases, which occur naturally in the atmosphere. This process plays a crucial role in warming the Earths surface, making it habitable. However, human-generated greenhouse gas emissions upset the natural balance and lead to increased warmth. How does this process work?
Incoming Energy • First, the Sun emits energy that is transmitted to Earth. Because the Sun is very hot, the energy is emitted in high- energy short wavelengths that penetrate the Earths atmosphere.
Absorption • About 30% of the Suns energy is reflected directly back into space by the atmosphere, clouds, and surface of the Earth. The rest of the Suns energy is absorbed into the Earths system.
Emission • The Earth emits energy into the atmosphere. Because the Earth is cooler than the Sun, the energy is emitted in the form of infrared radiation, at wavelengths longer than the incoming solar energy.
Role of Greenhouse Gases • Greenhouse gases in the atmosphere absorb much of the long-wave energy emitted from the Earths surface, preventing it from immediately escaping from the Earths system. The greenhouse gases then re-emit this energy in all directions, warming the Earths surface and lower atmosphere.
Human Role • The atmospheric concentration of greenhouse gases has increased over the past two centuries, largely due to human- generated carbon dioxide emissions from burning fossil fuels. This increase has amplified the natural greenhouse effect by trapping more of the energy emitted by the Earth. This change causes Earths surface temperature to increase.
Storms and Floods • Experts use climate models to project the impact rising global temperatures will have on precipitation. In just 30 years the occurrence of the strongest hurricanes - categories 4 and 5 - has nearly doubled. • Warm waters give hurricanes their strength, and scientists are correlating the increase in ocean and atmospheric temperatures to the rate of violent storms. Between 1905 and 2005 the frequency of hurricanes has been on a steady ascent. From 1905 to 1930, there were an average of 3.5 hurricanes per year; 5.1 between 1931 and 1994; and 8.4 between 1995 and 2005. 2005 saw a record number of tropical storms.
Shrinking Glaciers and Rising Sea Levels • Glaciers and ice shelves around the world are melting. The loss of large areas of ice on the surface could accelerate global warming because less of the suns energy would be reflected away from Earth to begin with (refer back to our discussion of the greenhouse effect). • An immediate result of melting glaciers would be a rise in sea levels. Initially, the rise in sea level would only be an inch or two. Even a modest rise in sea levels could cause flooding problems for low- lying coastal areas. However, if the West Antarctic Ice Sheet were to melt and collapse into the sea, it would push sea levels up 10 meters (more than 32 feet), and many coastal areas would completely disappear. The IPCC estimates that sea levels rose 17 centimeters (or about 6.7 inches) in the 20th century.
Drought • While some parts of the world may find themselves deluged by increasing storms and rising waters, other areas may find themselves suffering from drought. • As the climate warms, experts estimate drought conditions may increase by at least 66 percent. An increase in drought conditions leads quickly to a shrinking water supply and a decrease in quality agricultural conditions. This puts global food production and supply in danger and leaves populations at risk for starvation. • Today, India, Pakistan and sub-Saharan Africa already experience droughts, and experts predict precipitation could continue to dwindle in the coming decades. Estimates paint a dire picture. The Intergovernmental Panel on Climate Change suggests that by 2020, 75 to 250 million Africans may experience water shortages, and the continents agricultural output will decrease by 50 percent
Disease • Warmer temperatures along with associated floods and droughts are encouraging worldwide health threats by creating an environment where mosquitoes, ticks, mice and other disease-carrying creatures thrive. The World Health Organization (WHO) reports that outbreaks of new or resurgent diseases are on the rise and in more disparate countries than ever before. • While more than 150,000 people die from climate change-related sickness each year, everything from heat- related heart and respiratory problems to malaria are on the rise. Cases of allergies and asthma are also increasing.
Economic Consequences • The costs associated with climate change rise along with the temperatures. Severe storms and floods combined with agricultural losses cause billions of dollars in damages, and money is needed to treat and control. • Economic considerations reach into nearly every facet of our lives. Consumers face rising food and energy costs along with increased insurance premiums for health and homes. Governments suffer the consequences of diminished tourism and industrial profits, soaring energy, food and water demands, disaster cleanup and border tensions.
Loss of Biodiversity • Species loss and endangerment is rising along with global temperatures. As many as 30 percent of plant and animal species alive today risk extinction by 2050 if average temperatures rise more than 1.1 to 6.4 degrees. Such extinctions will be due to loss of habitat through desertification, deforestation and ocean warming, as well as the inability to adapt to climate warming. Wildlife researchers have noted some of the more resilient species migrating to distant lands to maintain their needed habitat. • Humans also arent immune to the threat. Desertification and rising sea levels threaten human habitats. And when plants and animals are lost to climate change, human food, fuel and income are lost as well.
Global Warming Case Studies • Glacial Retreat at Glacier National Park • Destruction of Coral Reefs • Narwhals in the Arctic
Glacial Retreat at Glacier National Park • Glaciers act as a “bank” of water whose continual melt helps regulate stream temperatures and maintains stream flow during late summer and drought periods when other sources are depleted. Without glacial melt water, summer water temperatures will increase and may cause the local extinction of temperature sensitive aquatic species, disrupting the basis of the aquatic food chain.
Glacial Retreat at Glacier National Park • Mountain snow packs hold less water and have begun to melt at least two weeks earlier in the spring. This impacts regional water supplies, wildlife, agriculture, and fire management. • Loss of alpine meadows will put some high-elevation species at risk as habitats become greatly diminished or eliminated. • Mountain pine beetle infestation will likely spread further, causing areas of forests to die which will impact wildlife and stream habitat, wildfire risk, and recreation use. • Fire frequency and burned area may be increased as fire season expands with earlier snowpack melt out and increasing number of hot days. Large fires may greatly impact regional air quality, increase risk to people and property, and negatively affect tourism.
Destruction of Coral Reefs • Increasing carbon dioxide in the atmosphere has a double effect on coral. Global warming means warmer seas, which causes the corals to bleach, where the creatures lose the symbiotic algae they need to survive. Carbon dioxide also makes seas more acidic, which means the corals find it difficult to prevent their exoskeletons from dissolving.
Destruction of Coral Reefs Reefs on the verge of destruction: • Florida Keys, United States The only coral reef system in the continental US and the third largest in the world, stretching 221 miles down the Florida coast. The US National Marine Fisheries Service says live coral is down 50-80% in the last decade, mainly due to damage by humans. • Jamaican reefs Threatened by sewage disposal, inland agricultural run-off and eutrophication, as well as tourist activities such as glass-bottom boat trips. Hurricanes hinder reef recovery and Caribbean coral cover has declined 80% in 25 years.
Destruction of Coral Reefs • Scarborough Reef, South China Sea Ownership disputes between the Philippines, mainland China and Taiwan mean the waters surrounding this reef are heavily overfished, and mangled by the blasts and cyanide used to maximize catch. • Seribu Islands, Java Sea, Indonesia Spanning over 108,000 hectares and 100 small islands, this reef is a significant contributor to the Indonesian tourism economy. Rapid urban development poses threats from domestic and industrial waste, urban run-off and oil and gas exploration. The 1997-1998 El Niño event triggered severe bleaching and killed over 90% of the coral down to 25 metres.
Narwhals in the Arctic • Global climate change researchers have categorized the narwhal as being the sea creature most at risk from global warming changes. • Polar bears, which have been generally considered the most “at-risk” animals from global warming, came in second place in the rankings. • Right now there are actually a lot more narwhals in the Arctic region (50,000 to 80,000) than polar bears (20,000). But researchers feel the overall impacts of global warming could have a quicker, more devastating impact on narwhals.
Narwhals in the Arctic • What’s the difference? Adaptability. Polar bears are able to gather food either by swimming or roaming land. As ice sheets diminish, they can forage for food on land. • Narwhals, on the other hand, are highly specialized creatures. A main feeding practice is diving to depths of 6,000 feet to feed on halibut. They live in areas with 99-percent ice cover. If that ice area diminishes, predators like orcas and polar bears will have easier access to getting to narwhals. And warming waters could send the narwhal’s favorite food of halibut to non-icy areas as well.
Intergovernmental Panel on Climate Change • The Intergovernmental Panel on Climate Change (IPCC) is a scientific intergovernmental body, set up at the request of member governments. • It was first established in 1988 by two UN organizations, the World Meteorological Organization (WMO) and the United Nations Environment Programme (UNEP), and later endorsed by the United Nations General Assembly through Resolution 43/53. • Its mission is to provide comprehensive scientific assessments of current scientific, technical and socio-economic information worldwide about the risk of climate change caused by human activity, its potential environmental and socio-economic consequences, and possible options for adapting to these consequences or mitigating the effects. • It is chaired by Rajendra K. Pachauri. The 2007 Nobel Peace Prize was shared, in two equal parts, between the IPCC and Al Gore.
Summary of the fourth assessment report, 2007 • Warming of the climate system is unequivocal • Very high confidence that global average net effect of human activities since 1750 one of warming • Human-caused warming over last 30 years has likely had a visible influence on many physical and biological systems • Continued GHG emissions at or above current rates would cause further warming and induce many changes in the global climate system during the 21st century that would very likely be larger than those observed during the 20th century.”
Strategies to reduce the damage caused by climate change • Produce more fuel-efficient vehicles • Reduce vehicle use • Improve energy-efficiency in buildings • Develop carbon capture and storage processes • Triple nuclear power • Increase solar power • Decrease deforestation/plant forests • Improve soil carbon management strategies
Individual Action • Challenge others about global warming. • Recycle more by using recycling bins, composting, etc. • Use compact fluorescent bulbs and LED light bulbs. • Use recycled paper. • Replace old appliances and reduce reliance on them. • Unplug unused electronics. • Purchase hybrid cars. • Use public transportation. • Ride a bicycle.