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Climate Change

Climate change Climate change is a significant and lasting change in the statistical distribution of weather patterns over periods ranging from decades to millions of years. It may be a change in average weather conditions or the distribution of events around that average (e. g. , more or fewer extreme weather events). Climate change may be limited to a specific region or may occur across the whole Earth, such as global warming. Terminology The most general definition of climate change is a change in the statistical properties of the climate system when considered over long periods of time, regardless of cause. 1][2] Accordingly, fluctuations over periods shorter than a few decades, such as El Nino, do not represent climate change. The term sometimes is used to refer specifically to climate change caused by human activity, as opposed to changes in climate that may have resulted as part of Earth’s natural processes. [3] In this latter sense, used especially in the context of environmental policy, the term climate change today is synonymous with anthropogenic global warming.

Within scientific journals, however, global warming refers to surface temperature increases, while climate change includes global warming and everything else that increasing greenhouse gas amounts will affect. Climate Change is the emission of greenhouse gases like C02 and methane is the result of industrialization other improper practices, which result into their production. The ozone layer which protects life on earth from ultraviolet (UV) radiations is becoming thinner gradually due to these greenhouse gases. The greenhouse gas emissions adversely affect our environment and are the underlying cause of the global warming phenomenon.

There is a gradual shift in the patterns of climate observed over many years; it is therefore one of the global environmental issues. Understanding the different causes and factors associated with climate change is therefore important. Causes Climate changes in response to changes in the global energy balance. On the broadest scale, the rate at which energy is received from the sun and the rate at which it is lost to space determine the equilibrium temperature and climate of Earth. This energy is then distributed around the globe by winds, ocean currents, and other mechanisms to affect the climates of different regions.

Factors that can shape climate are called climate forcings or “forcing mechanisms”. [5] These include such processes as variations in solar radiation, deviations in the Earth’s orbit, mountain-building and continental drift, and changes in greenhouse gas concentrations. There are a variety of climate change feedbacks that can either amplify or diminish the initial forcing. Some parts of the climate system, such as the oceans and ice caps, respond slowly in reaction to climate forcings, while others respond more quickly. Forcing mechanisms can be either “internal” or “external”.

Internal forcing mechanisms are natural processes within the climate system itself (e. g. , the meridional overturning circulation). External forcing mechanisms can be either natural (e. g. , changes in solar output) or anthropogenic (e. g. , increased emissions of greenhouse gases). Whether the initial forcing mechanism is internal or external, the response of the climate system might be fast (e. g. , a sudden cooling due to airborne volcanic ash reflecting sunlight), slow (e. g. thermal expansion of warming ocean water), or a combination (e. g. sudden loss of albedo in the arctic ocean as sea ice melts, followed by more gradual thermal expansion of the water). Therefore, the climate system can respond abruptly, but the full response to forcing mechanisms might not be fully developed for centuries or even longer. Climate is the general condition of the atmosphere over a large geographical area for a minimum period of thirty years. Thus naturally, change in climate of a particular region ought to be a gradual process if it happens at all. In fact, many people may not live to see a perceptible change in their lifetime.

Yet, nowadays we hear many reports of the global climate undergoing changes. Many reasons are attributed to these, primary being radiation from the Sun, deviation in the orbit of the Earth, continental drift and mountain building and changes in the concentration of greenhouse gases. The tectonic plates and their motions are responsible for the topographical condition of the planet. They decide the size, proportions, positions, etc of the landmass and the water bodies. Thus with their irregular movements, the current climatic distribution can change if the topographical map alters even a bit.

The main source of energy on earth is the solar radiation. But if the intensity of this radiation increases, then the overall temperature of the globe will increase. This is said to be happening now, in the name of global warming. It is said that three or four billion years ago, the Sun produced 70 percent of today’s amount of radiation. Since climate of any place is dependent on the temperature, the overall climatic conditions will also change. The slight variations in the orbit of the Earth have resulted in altered distribution of sun rays.

The places which did not use to get that much sunlight before get it now and vice versa. Apart from the natural causes, humans and their activities are also largely responsible for the change in the climatic conditions of the Earth today. Climate changes are usually long-term changes, in regular weather patterns which is usually over a specific region in a period of time which is irreversible. There are some major causes which causes climate to change. There are numbers of variation in the solar activity, which are getting observed through the years, studying the sunspots and the beryllium isotopes.

Sun provides the earth with high amount of heat energy, as the main part of climate. This solar variation triggers a phenomenon called global warming, which caused climatic change throughout the earth. The elliptical orbit which is taken by Earth around sun also plays an important role in distribution of the amount of sunrays, which reaches the surface of earth. This has a great impact on season change. Landmass on the earth is made of big plates called plate tectonics, which rub against each other and sometimes drift apart. Which then results tear and wear of mountains, carbon stored in the layers also increased glaciations.

The geysers and volcanic eruptions release a type of particulates into Earth’s atmosphere which also causes climate to change. Climate changes results to from atmosphere-ocean relationship. Climate fluctuations like Arctic oscillation and El Nino Southern oscillation, acts as huge heat-reservoirs inside the oceans. The Thermohaline circulation is redistribution of  heat in form of deep and slow oceanic currents. Direct or indirect causes influenced by the human activity. Direct factors like the release of the aerosols, combustion of fossil fuel and CO2 emissions causes climatic change.

Indirect causes, like increase in the greenhouse gasses, and increased level of water pollution and land pollution, also caused a great deal in climatic change. This climatic change causes rapid deterioration to the environment. Internal forcing mechanisms Natural changes in the components of earth’s climate system and their interactions are the cause of internal climate variability, or “internal forcings. ” Scientists generally define the five components of earth’s climate system to include Atmosphere, hydrosphere, cryosphere, lithosphere (restricted to the surface soils, rocks, and sediments), and biosphere. [6][citation needed]

Ocean variability Pacific Decadal Oscillation 1925 to 2010 Main article: Thermohaline circulation The ocean is a fundamental part of the climate system, some changes in it occurring at longer timescales than in the atmosphere, massing hundreds of times more and having very high thermal inertia (such as the ocean depths still lagging today in temperature adjustment from the Little Ice Age). [7] Short-term fluctuations (years to a few decades) such as the El Nino-Southern Oscillation, the Pacific decadal oscillation, the North Atlantic oscillation, and the Arctic oscillation, represent climate variability rather than climate change.

On longer time scales, alterations to ocean processes such as thermohaline circulation play a key role in redistributing heat by carrying out a very slow and extremely deep movement of water, and the long-term redistribution of heat in the world’s oceans. A schematic of modern thermohaline circulation. Tens of millions of years ago, continental plate movement formed a land-free gap around Antarctica, allowing formation of the ACC which keeps warm waters away from Antarctica. External forcing mechanisms Increase in Atmospheric CO2 Levels Milankovitch cycles from 800,000 years ago in the past to 800,000 years in the future.

Variations in CO2, temperature and dust from the Vostok ice core over the last 450,000 years Orbital variations Main article: Milankovitch cycles Slight variations in Earth’s orbit lead to changes in the seasonal distribution of sunlight reaching the Earth’s surface and how it is distributed across the globe. There is very little change to the area-averaged annually averaged sunshine; but there can be strong changes in the geographical and seasonal distribution. The three types of orbital variations are variations in Earth’s eccentricity, changes in the tilt angle of Earth’s axis of rotation, and precession of Earth’s axis.

Combined together, these produce Milankovitch cycles which have a large impact on climate and are notable for their correlation to glacial and interglacial periods,[8] their correlation with the advance and retreat of the Sahara,[8] and for their appearance in the stratigraphic record. [9] The IPCC notes that Milankovitch cycles drove the ice age cycles; CO2 followed temperature change “with a lag of some hundreds of years”; and that as a feedback amplified temperature change. [10] The depths of the ocean have a lag time in changing temperature (thermal inertia on such scale).

Upon seawater temperature change, the solubility of CO2 in the oceans changed, as well as other factors impacting air-sea CO2 exchange. [11] Solar output Main article: Solar variation Variations in solar activity during the last several centuries based on observations of sunspots and beryllium isotopes. The period of extraordinarily few sunspots in the late 17th century was the Maunder Minimum. The sun is the predominant source for energy input to the Earth. Both long- and short-term variations in solar intensity are known to affect global climate.

Three to four billion years ago the sun emitted only 70% as much power as it does today. If the atmospheric composition had been the same as today, liquid water should not have existed on Earth. However, there is evidence for the presence of water on the early Earth, in the Hadean[12][13] and Archean[14][12] eons, leading to what is known as the faint young sun paradox. [15] Hypothesized solutions to this paradox include a vastly different atmosphere, with much higher concentrations of greenhouse gases than currently exist. 16] Over the following approximately 4 billion years, the energy output of the sun increased and atmospheric composition changed. The oxygenation of the atmosphere around 2. 4 billion years ago was the most notable alteration. Over the next five billion years the sun’s ultimate death as it becomes a red giant and then a white dwarf will have large effects on climate, with the red giant phase possibly ending any life on Earth that survives until that time. Solar output also varies on shorter time scales, including the 11-year solar cycle[17] and longer-term modulations. 18] Solar intensity variations are considered to have been influential in triggering the Little Ice Age,[19] and some of the warming observed from 1900 to 1950. The cyclical nature of the sun’s energy output is not yet fully understood; it differs from the very slow change that is happening within the sun as it ages and evolves. Research indicates that solar variability has had effects including the Maunder Minimum from 1645 to 1715 A. D. , part of the Little Ice Age from 1550 to 1850 A. D. which was marked by relative cooling and greater glacier extent than the centuries before and afterward. 20][21] Some studies point toward solar radiation increases from cyclical sunspot activity affecting global warming, and climate may be influenced by the sum of all effects (solar variation, anthropogenic radiative forcings, etc. ). [22][23]. Interestingly, a 2010 study[24] suggests, “that the effects of solar variability on temperature throughout the atmosphere may be contrary to current expectations. ” In an Aug 2011 Press Release[25], CERN announced the publication in the Nature journal the initial results from its CLOUD experiment.

The results indicate that ionisation from cosmic rays significantly enhances aerosol formation in the presence of sulphuric acid and water, but in the lower atmosphere where ammonia is also required, this is insufficient to account for aerosol formation and additional trace vapours must be involved. The next step is to find more about these trace vapours, including whether thay are of natural or human origin. Volcanism In atmospheric temperature from 1979 to 2010, determined by MSU NASA satellites, effects appear from aerosols released by major volcanic eruptions (El Chichon and Pinatubo).

El Nino is a separate event, from ocean variability. Volcanic eruptions release gases and particulates into the atmosphere. Eruptions large enough to affect climate occur on average several times per century, and cause cooling (by partially blocking the transmission of solar radiation to the Earth’s surface) for a period of a few years. The eruption of Mount Pinatubo in 1991, the second largest terrestrial eruption of the 20th century[26] (after the 1912 eruption of Novarupta[27]) affected the climate substantially.

Global temperatures decreased by about 0. 5 °C (0. 9 °F). The eruption of Mount Tambora in 1815 caused the Year Without a Summer. [28] Much larger eruptions, known as large igneous provinces, occur only a few times every hundred million years, but may cause global warming and mass extinctions. [29] Volcanoes are also part of the extended carbon cycle. Over very long (geological) time periods, they release carbon dioxide from the Earth’s crust and mantle, counteracting the uptake by sedimentary rocks and other geological carbon dioxide sinks.

The US Geological Survey estimates are that volcanic emissions are at a much lower level than than the effects of current human activities, which generate 100-300 times the amount of carbon dioxide emitted by volcanoes. [30] A review of published studies indicates that annual volcanic emissions of carbon dioxide, including amounts released from mid-ocean ridges, volcanic arcs, and hot spot volcanoes, are only the equivalent of 3 to 5 days of human caused output. The annual amount put out by human activities may be greater than the amount released by supererruptions, the most recent of which was the Toba eruption in Indonesia 74,000 years ago. 31] Although volcanoes are technically part of the lithosphere, which itself is part of the climate system, IPCC explicitly defines volcansim as an external forcing agent. [32] Plate tectonics Over the course of millions of years, the motion of tectonic plates reconfigures global land and ocean areas and generates topography. This can affect both global and local patterns of climate and atmosphere-ocean circulation. [33] The position of the continents determines the geometry of the oceans and therefore influences patterns of ocean circulation.

The locations of the seas are important in controlling the transfer of heat and moisture across the globe, and therefore, in determining global climate. A recent example of tectonic control on ocean circulation is the formation of the Isthmus of Panama about 5 million years ago, which shut off direct mixing between the Atlantic and Pacific Oceans. This strongly affected the ocean dynamics of what is now the Gulf Stream and may have led to Northern Hemisphere ice cover. [34][35] During the Carboniferous period, about 300 to 360 million years ago, plate tectonics may have triggered large-scale storage of carbon nd increased glaciation. [36] Geologic evidence points to a “megamonsoonal” circulation pattern during the time of the supercontinent Pangaea, and climate modeling suggests that the existence of the supercontinent was conducive to the establishment of monsoons. [37] The size of continents is also important. Because of the stabilizing effect of the oceans on temperature, yearly temperature variations are generally lower in coastal areas than they are inland. A larger supercontinent will therefore have more area in which climate is strongly seasonal than will several smaller continents or islands.

Human influences Main article: Global warming In the context of climate variation, anthropogenic factors are human activities which affect the climate. The scientific consensus on climate change is “that climate is changing and that these changes are in large part caused by human activities,”[38] and it “is largely irreversible. “[39] “Science has made enormous inroads in understanding climate change and its causes, and is beginning to help develop a strong understanding of current and potential impacts that will affect people today and in coming decades.

This understanding is crucial because it allows decision makers to place climate change in the context of other large challenges facing the nation and the world. There are still some uncertainties, and there always will be in understanding a complex system like Earth’s climate. Nevertheless, there is a strong, credible body of evidence, based on multiple lines of research, documenting that climate is changing and that these changes are in large part caused by human activities.

While much remains to be learned, the core phenomenon, scientific questions, and hypotheses have been examined thoroughly and have stood firm in the face of serious scientific debate and careful evaluation of alternative explanations. ” — United States National Research Council, Advancing the Science of Climate Change Consequently, the debate is shifting onto ways to reduce further human impact and to find ways to adapt to change that has already occurred [40] and is anticipated to occur in the future. [41]

Of most concern in these anthropogenic factors is the increase in CO2 levels due to emissions from fossil fuel combustion, followed by aerosols (particulate matter in the atmosphere) and cement manufacture. Other factors, including land use, ozone depletion, animal agriculture[42] and deforestation, are also of concern in the roles they play – both separately and in conjunction with other factors – in affecting climate, microclimate, and measures of climate variables. Physical evidence for and examples of climatic change Comparisons between Asian Monsoons from 200 A. D. o 2000 A. D. (staying in the background on other plots), Northern Hemisphere temperature, Alpine glacier extent (vertically inverted as marked), and human history as noted by the U. S. NSF. Arctic temperature anomalies over a 100 year period as estimated by NASA. Typical high monthly variance can be seen, while longer-term averages highlight trends. Evidence for climatic change is taken from a variety of sources that can be used to reconstruct past climates. Reasonably complete global records of surface temperature are available beginning from the mid-late 19th century.

For earlier periods, most of the evidence is indirect—climatic changes are inferred from changes in proxies, indicators that reflect climate, such as vegetation, ice cores,[43] dendrochronology, sea level change, and glacial geology. Earth’s climates have changed throughout the history. Satellites which go round the earth and technological advanced equipments enabled a scientist to watch a bigger picture, thus collecting various information regarding earth and its climatic change across the globe.

Studying these data which is collected over the years shows evidence for the changing climate. There are various evidences for the change in climate, over the years. Thel sea level had risen about 17 6. 7 inches in the last 100 years. In the previus10 years the rate was nearly the double of last century. All 3 global surface temperature reconstruction show that earth had warmed up since the year 1880. Most of the warming had occurred in the 1970s. Though people had tried to their best, the temperature is rising day by day.

The oceans absorbed the increased heat, with its top, which is about 2,300 feet of ocean shows warming of water up to 0. 302 degrees F, since the year 1969. The Antarctic and Greenland sheets of ice have decreased, in mass. According to” NASA’s Gravity Recovery and Climate Experiment show”, Greenland lost around 150 to 250 cubic km, of ice every year, between, the years 2002 and 2006; on the other hand, Antarctica lost over 152 cubic km of ice, within, the years 2002 and 2006. The thickness and extent, of the Arctic sea, ice has rapidly declined over the previous 10 years.

Glaciers started retreating everywhere around world — including the Alps, Andes, Himalayas, Africa Rockies and Alaska. The CO2 content of  oceans is increasing since the year 1750, it has currently increased to up to two billion tons every year, which has increased the ocean acidity up to 30%. The numbers of high record temperature event, in U S is increasing, while the numbers of low temperature record events, is decreasing, since the year 1950. The numbers of rainfall events are also increasing in the US. Temperature measurements and proxies

The instrumental temperature record from surface stations was supplemented by radiosonde balloons, extensive atmospheric monitoring by the mid-20th century, and, from the 1970s on, with global satellite data as well. The 18O/16O ratio in calcite and ice core samples used to deduce ocean temperature in the distant past is an example of a temperature proxy method, as are other climate metrics noted in subsequent categories. Historical and archaeological evidence Main article: Historical impacts of climate change Climate change in the recent past may be detected by corresponding changes in settlement and agricultural patterns. 44] Archaeological evidence, oral history and historical documents can offer insights into past changes in the climate. Climate change effects have been linked to the collapse of various civilizations. [44] Decline in thickness of glaciers worldwide over the past half-century Glaciers Glaciers are considered among the most sensitive indicators of climate change. [45] Their size is determined by a mass balance between snow input and melt output. As temperatures warm, glaciers retreat unless snow precipitation increases to make up for the additional melt; the converse is also true.

Glaciers grow and shrink due both to natural variability and external forcings. Variability in temperature, precipitation, and englacial and subglacial hydrology can strongly determine the evolution of a glacier in a particular season. Therefore, one must average over a decadal or longer time-scale and/or over a many individual glaciers to smooth out the local short-term variability and obtain a glacier history that is related to climate. A world glacier inventory has been compiled since the 1970s, initially based mainly on aerial photographs and maps but now relying more on satellites.

This compilation tracks more than 100,000 glaciers covering a total area of approximately 240,000 km2, and preliminary estimates indicate that the remaining ice cover is around 445,000 km2. The World Glacier Monitoring Service collects data annually on glacier retreat and glacier mass balance From this data, glaciers worldwide have been found to be shrinking significantly, with strong glacier retreats in the 1940s, stable or growing conditions during the 1920s and 1970s, and again retreating from the mid 1980s to present. [46]

The most significant climate processes since the middle to late Pliocene (approximately 3 million years ago) are the glacial and interglacial cycles. The present interglacial period (the Holocene) has lasted about 11,700 years. [47] Shaped by orbital variations, responses such as the rise and fall of continental ice sheets and significant sea-level changes helped create the climate. Other changes, including Heinrich events, Dansgaard–Oeschger events and the Younger Dryas, however, illustrate how glacial variations may also influence climate without the orbital forcing.

Glaciers leave behind moraines that contain a wealth of material—including organic matter, quartz, and potassium that may be dated—recording the periods in which a glacier advanced and retreated. Similarly, by tephrochronological techniques, the lack of glacier cover can be identified by the presence of soil or volcanic tephra horizons whose date of deposit may also be ascertained. This time series, based on satellite data, shows the annual Arctic sea ice minimum since 1979. The September 2010 extent was the third lowest in the satellite record. Arctic sea ice loss

Main articles: Polar ice packs and Climate change in the Arctic The decline in Arctic sea ice, both in extent and thickness, over the last several decades is further evidence for rapid climate change. [48] Sea ice is frozen seawater that floats on the ocean surface. It covers millions of square miles in the polar regions, varying with the seasons. In the Arctic, some sea ice remains year after year, whereas almost all Southern Ocean or Antarctic sea ice melts away and reforms annually. Satellite observations show that Arctic sea ice is now declining at a rate of 11. percent per decade, relative to the 1979 to 2000 average. [49] Vegetation A change in the type, distribution and coverage of vegetation may occur given a change in the climate. Some changes in climate may result in increased precipitation and warmth, resulting in improved plant growth and the subsequent sequestration of airborne CO2. Larger, faster or more radical changes, however, may result in vegetation stress, rapid plant loss and desertification in certain circumstances. [50][51] An example of this occurred during the Carboniferous Rainforest Collapse (CRC), an extinction event 300 million years ago.

At this time vast rainforests covered the equatorial region of Europe and America. Climate change devastated these tropical rainforests, abruptly fragmenting the habitat into isolated ‘islands’ and causing the extinction of many plant and animal species. [50] Satellite data available in recent decades indicates that global terrestrial net primary production increased by 6% from 1982 to 1999, with the largest portion of that increase in tropical ecosystems, then decreased by 1% from 2000 to 2009. [52][53] Food Safety And Climate Change

Climatic change has various aspects and does not refer to increased average global temperature only. Other effects include effects on rainfall, trends towards storms and arid periods. All these changes can affect food safety and food production. Crop production can be severely affected by climatic change. A change in the climate is rather likely, to reduce the yields and damage crops. However, effects might vary in various regions of the world. Even a small change in distribution of the rainfall can severely affect agriculture, particularly in tropical areas.

A big increase in temperature would shift the limits of regions where crops grow pole-ward. However, a big increase in mean temperature of about 2°C could increase potential evaporation by 10%, leading ahead to drying up of crops and more requirements for water. Increases in temperature will accelerate the crop growth, shortening its growth period and leading for reduced yield. Climatic change affects the pests and also the microbial population present in soil. All these affect crop yield. Climatic change affects animal productions. Heat stress can affect health, reproduction and growth of livestock.

Change in the availability of livestock forage and feeds can also have an effect and such changes is rather likely to be more dramatic especially in the temperate regions. Ensuring safety of food during such global climate changes can be a complex task. Safety of Food hazards can possibly arise at any stage of food production. Assuring safety of food requires a good understanding of possible changes which may occur ensuring that the world is prepared for those changes. It also involves implementation of better agricultural practices. Pollen analysis

Palynology is the study of contemporary and fossil palynomorphs, including pollen. Palynology is used to infer the geographical distribution of plant species, which vary under different climate conditions. Different groups of plants have pollen with distinctive shapes and surface textures, and since the outer surface of pollen is composed of a very resilient material, they resist decay. Changes in the type of pollen found in different layers of sediment in lakes, bogs, or river deltas indicate changes in plant communities. These changes are often a sign of a changing climate. 54][55] As an example, palynological studies have been used to track changing vegetation patterns throughout the Quaternary glaciations[56] and especially since the last glacial maximum. [57] Top: Arid ice age climate Middle: Atlantic Period, warm and wet Bottom: Potential vegetation in climate now if not for human effects like agriculture. [58] Precipitation Past precipitation can be estimated in the modern era with the global network of precipitation gauges. Surface coverage over oceans and remote areas is relatively sparse, but, reducing reliance on interpolation, satellite data has been available since the 1970s. 59] Quantification of climatologically variation of precipitation in prior centuries and epochs is less complete but approximated using proxies such as marine sediments, ice cores, cave stalagmites, and tree rings. [60] Climatologically temperatures substantially affect precipitation. For instance, during the Last Glacial Maximum of 18,000 years ago, thermal-driven evaporation from the oceans onto continental landmasses was low, causing large areas of extreme desert, including polar deserts (cold but with low rates of precipitation). 58] In contrast, the world’s climate was wetter than today near the start of the warm Atlantic Period of 8000 years ago. [58] Estimated global land precipitation increased by approximately 2% over the course of the 20th century, though the calculated trend varies if different time endpoints are chosen, complicated by ENSO and other oscillations, including greater global land precipitation in the 1950s and 1970s than the later 1980s and 1990s despite the positive trend over the century overall. 59][61][62] Similar slight overall increase in global river runoff and in average soil moisture has been perceived. [61] Dendroclimatology Dendroclimatology is the analysis of tree ring growth patterns to determine past climate variations. [63] Wide and thick rings indicate a fertile, well-watered growing period, whilst thin, narrow rings indicate a time of lower rainfall and less-than-ideal growing conditions. Ice cores Analysis of ice in a core drilled from a ice sheet such as the Antarctic ice sheet, can be used to show a link between temperature and global sea level variations.

The air trapped in bubbles in the ice can also reveal the CO2 variations of the atmosphere from the distant past, well before modern environmental influences. The study of these ice cores has been a significant indicator of the changes in CO2 over many millennia, and continues to provide valuable information about the differences between ancient and modern atmospheric conditions. Animals Remains of beetles are common in freshwater and land sediments. Different species of beetles tend to be found under different climatic conditions. Given the extensive lineage of beetles whose genetic makeup has not altered ignificantly over the millennia, knowledge of the present climatic range of the different species, and the age of the sediments in which remains are found, past climatic conditions may be inferred. [ Variation in Pacific salmon catch over the 20th century and correlation with a climate-related Atmospheric Circulation Index (ACI) as estimated by the U. N. FAO. Similarly, the historical abundance of various fish species has been found to have a substantial relationships with observed climatic conditions. Changes in the primary productivity of autotrophs in the oceans can affect marine food webs. [ Sea level change

Main articles: Sea level and Current sea level rise Global sea level change for much of the last century has generally been estimated using tide gauge measurements collated over long periods of time to give a long-term average. More recently, altimeter measurements — in combination with accurately determined satellite orbits — have provided an improved measurement of global sea level change. To measure sea levels prior to instrumental measurements, scientists have dated coral reefs that grow near the surface of the ocean, coastal sediments, marine terraces, ooids in limestone, and near shore archaeological remains.

The predominant dating methods used are uranium series and radiocarbon, with cosmogenic radionuclides being sometimes used to date terraces that have experienced relative sea level fall. Climate Change Bill Summary Also called “the Climate Change Bill” and “the Waxman-Markey Bill (after the name of its authors, Henry A. Waxman & Edward J. Markey), “the American Clean Energy and Security Act” (2009) is a bill tabled in 111th US Congress. It proposed a system, where the government is set an upper limit to the amount of different greenhouse gases (for example: carbon dioxide, methane, chlorofluorocarbons) which usually gets emitted per year.

Called the “cap and trade system”, this bill would set a limit on total emissions of greenhouse gases during the period 2012 to 2050. The limit would gradually be reduced over time to lower emissions of greenhouse gases. Thus companies would need to buy special permits to emit these gases (especially for carbon dioxide) and companies who emit more gases would have to pay more. This would provide an incentive to lower emissions. Other elements in the bill include: A “renewable electricity standard” under which companies producing electricity who supply over 4 million MWh , which produce  around 20% of the electricity through renewable sources of energy by 2020. * Consumers would be protected from the energy price rises. * Emissions of the greenhouse gases like methane and carbon dioxide should be reduced by 17% from the year 2005, levels by the year 2020. Overall, this could lead to an 80% reduction in greenhouse gas emission by the US by 2050. * Techniques for development of “clean energy technologies and energy efficiency” would be subsidized with $90 billion, in subsidies by the year 2025.

This would include subsidies for carbon capture, vehicles powered by electricity and other sources of energy and scientific research for development of alternative sources of energy. How Climate Change Affects Society? After decades of battle, scientists and experts have now become successful in making people see that changes in the climate around them s actually happening. They are also working to make all of us aware of all the factors associated with it, the causes behind this change and the probable steps that we can take to prevent it from worsening further.

If the climate continues to change in the present rate, it would not be long before the world sees a drastic change in all the ecological, natural and social spheres of the world. We shall discuss about the effects climatic changes can bring about in the society in this article. By society, we mean the human beings along with their habitat, in this topic. If the predictions regarding the differences the world will experience in the near future in terms of the climate surrounding them come true, then it would not be long before a large mass of the Earth sinks below the sea level.

This is because will rapid increase in temperature of the world, the ice caps and glaciers have started to melt. This has resulted in a small but significant increase in the level of water on the planet. Now if this continues, the low lying coastal areas would be the first type of human habitat to be affected. This would bring down the population in those areas disastrously. Now, the present human health is adapted to a particular climate depending on the place of inhabitance of a particular human being. But with the sudden changes in the climatic conditions, the health of the humans may not get adjusted to it so quickly.

That would also affect the human population to a certain extent. Now if the population of our race becomes affected, automatically our society falls under the risk of getting disintegrated. How Did Climate Change Start ? Change in climate is a very slow process as it involves a huge geographical area and a lot of time, stretching to even millions of years. Even though it might have started way before but scientifically, change in climate has been discovered in the nineteenth century. At this time, paleoclimatic changes were suspected and the effects of natural greenhouse gases were first noticed.

Later in that century, scientist began to wonder whether emission of greenhouse gases by the human beings could contribute to the climatic changes or not. By the 1980s, experts understood that humans and their activities are the main causes behind the warming up of the climate. This led to the beginning of the global warming science, as summarized by the Intergovernmental Panel on Climate Change. Before the 18th century, scientists did not differentiate prehistoric climate from the modern one. Geologists, later that century, found evidences supporting geological age’s succession with respect to climatic changes.

In the year 1819, Jean-Pierre Perraudin suspected that glaciers might be the reason behind the huge boulders of alpine valleys. Despite meeting with initial rejection, this theory went to the ears of Louis Agassiz, an influential scientist, who then came up with the concept of Ice Age. In 1824, another scientist named Joseph Fourier came up with the idea that the atmosphere of the earth kept it warmer as compared to vacuum. He first identified the transmission of visible light waves through the atmosphere to the earth.

Finally, in 1988, the Intergovernmental Panel on Climate Change was established which till date, continues to address the issues of global warming and climatic changes on earth. The Impacts of Global Warming And Climate Change Global warming and climatic changes are the hot topics of discussion of the modern world. This is because the world is now experiencing significant changes in the global temperature and climate conditions. At first, many people and even big organizations were neglecting the reports of changes in the world climatic conditions.

But as the years are progressing, the people also are taking notice about the alterations that are taking place around them. If neglected beyond this point, global warming and change in climate can produce adverse results. Global warming, for example, can produce far-reaching effects in the social, ecological and natural systems. The glaciers at the north and south poles of the Earth are reportedly melting at a steady pace. If this continues for a few more years, the average sea level of the world would rise to such a level that it would submerge many of the largely inhabited places in the planet.

Statistics say that the global sea level may increase by 0. 18 m to 0. 59 m by the end of the 21st century. Change in the conditions of the climate can result in affecting tundra, coral reef and mangroves ecosystem adversely. This will be due to increase in carbon dioxide levels due to increase in overall temperature of the regions. This may lead to many species being extinct from the world. As far as the social system is concerned, climatic changes can affect the low lying coastal areas largely. This is because these areas run the most risk of getting submerged due to increased sea level.

This will affect the human population there. Moreover, health of the humans may not get adapted so quickly to the new climatic conditions. So that might affect the overall status of the race to Copenhagen Climate Change Treaty The Copenhagen Climate Change treaty got drafted by the US, India, China, South Africa and Brazil, at the 15th session, of Conference of the Parties in 2009. It is still not legally bound on any country. The treaty has the following provisions: * It recommends continuation of Kyoto Protocol. It points out that the climate change is the greatest of all the challenges facing the world and a political will is urgently needed to combat it. * It endorses that “the increase in global temperature should be below 2 degrees Celsius” in order that it combats the change in climate. * It endorses that serious cuts in the global emissions, that are required and a low emission strategy needs to be employed for sustainable development. * It recognizes that forests play an important role in removing greenhouse gases and forest degradation and deforestation play a role in controlling emissions. It recognizes that “enhanced action and international cooperation on adaptation is urgently required” so it provides resilience particularly in the developing countries * It sets a target for our world to raise about $100 billion every year by the year 2020 from various sources to help countries cut down on carbon emissions. * It calls for assessments of the implementations of the Accord which is to be completed by the year 2015”. * Till date, countries producing over 80 percent global emissions have signed Copenhagen Accord. Global Solution For Climate Change Change in climatic condition is happening all around the globe today.

Several factors, both natural and artificial are found to be behind this phenomenon. Now, the consequences of this phenomenon are also understood to be quite far-reaching. The temperature all around the planet is seen to be increasing because of increased intensity of solar radiation. Due to this sudden heating up, the glaciers at both the poles of the earth have started to melt. This made the global sea level to rise up significantly, causing concern to people staying in low-lying (submergible) areas everywhere. Scientists are calling this phenomenon of increase in temperature all around the world as global warming.

And it is not a good sign. Thus all the nations in the world should put their thoughts together to find a solution to curb this problem as it will affect the whole human race if neglected from now on. Already 192 nations including the US have participated in the annual meet of the United Nations Framework Convention on Climate Change to address this problem. But more needs to be done. More people should be made aware of the problems we are facing now. Sadly, there are many organizations rubbishing the reports of global climatic changes as rumors and thus creating a false sense of security.

This should be stopped and more people should be involved in coming up with some answers to this problem. At this stage, we, as human beings can at least control the man-made factors affecting this global climatic condition. That will bring about some change in the initial stage before a better solution is thought of. Reaction (Reflection) I would be more concerned if we didn’t have climate change than if we did. If it wasn’t for climate change we’d still be in the last ice age! The Earth’s climate goes through cycles since the Earth has had an atmosphere, it doesn’t care if the species on the planet can adapt to it, it just changes.

Those that adapt survive those that cannot go extinct… survival of the fittest. Do we have a moral obligation to help people should climate change cause a threat to humanity, yes… but should we go all chicken little because our models are predicting a temperature increase… no. We can only give an educated guess of what will occur, but I am pretty sure humans will adapt to climate change because we are a resilient species and we have the technology to survive. References 1. ^ “Glossary – Climate Change”. Education Center – Arctic Climatology and Meteorology.

NSIDC National Snow and Ice Data Center. http://nsidc. org/arcticmet/glossary/climate_change. html. 2. ^ Houghton, John Theodore, ed (2001). “Appendix I – Glossary”. Climate change 2001: the scientific basis: contribution of Working Group I to the Third Assessment Report of the Intergovernmental Panel on Climate Change. Cambridge, UK: Cambridge University Press. ISBN 0-521-80767-0. http://www. ipcc. ch/ipccreports/tar/wg1/518. htm. 3. ^ “The United Nations Framework Convention on Climate Change”. 21 March 1994. http://unfccc. int/essential_background/convention/background/items/1349. php. Climate change means a change of climate which is attributed directly or indirectly to human activity that alters the composition of the global atmosphere and which is in addition to natural climate variability observed over comparable time periods. ”  4. ^ “What’s in a Name? Global Warming vs. Climate Change”. NASA. http://www. nasa. gov/topics/earth/features/climate_by_any_other_name. html. Retrieved 23 July 2011. 5. ^ US EPA. Glossary of climate change terms. http://www. epa. gov/climatechange/glossary. html#F. 6. ^ “Glossary”. NASA Earth Observatory. 2011. http://earthobservatory. nasa. gov/Glossary/index. hp? mode=alpha&seg=b&segend=d. Retrieved 8 July 2011. “Climate System: The five physical components (atmosphere, hydrosphere, cryosphere, lithosphere, and biosphere) that are responsible for the climate and its variations. ”  7. ^ Kirk Bryan, Geophysical Fluid Dynamics Laboratory. Man’s Great Geophysical Experiment. U. S. National Oceanic and Atmospheric Administration. 8. ^ a b “Milankovitch Cycles and Glaciation”. University of Montana. http://www. homepage. montana. edu/~geol445/hyperglac/time1/milankov. htm. Retrieved 2009-04-02. 9. ^ Gale, Andrew S. (1989). “A Milankovitch scale for Cenomanian time”.

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