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HUMAN INFLUENCE ON CLIMATE |
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by Meena Pandey | 06-10-2019 23:24
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Human Influence on climate Greenhouse gases Weather related disasters such as drought, flooding, forest fires, ice storm, snowstorms, dusts Troms , landslides, hailstorms, are not uncommon in any regions of the year. GHGs are the atmospheric constitutes which are transparent to (incoming) short wave radiation & have the property of absorbing (outgoing) long wave radiation & and o Short wave radiation: 0.15-4 μ (solar radiation) o Long wave radiation: 4-100 μ (terrestrial radiation, nocturnal radiation) It means they reradiate the long wave radiation back to the surface. CO2, Water vapor, CO4, CO, Sulphur, Nitrous oxides (N2O), chlorofluoro carbons & chlorofluoromethanes are the major GHGs. In this process, earth atmosphere warms up & its temperature rises. It is known as greenhouse (GH) effects. Many GHGs occur naturally, such as water vapor, CO2, CO4, (N2O). Others such as hydrofluorocarbons (HFCs), perfluorocarbons (PFCs), & sulfur hexafluoride (SF6) result exclusively from human industrial processes. Human activities also add significantly to the level of naturally occurring greenhouse gases. CO2 is released into atmosphere by burning of solid waste, wood & wood products, & fossil fuels (oil, natural gas, & coal). N2O emissions occur during various agricultural & industrial processes, & when solid waste or fossil fuels are burned. CH4 is emitted when organic waste decomposes under anaerobic condition, whether in landfills or in connection with livestock farming. CH4 emissions also occur during production & transport of fossil fuels. Agricultural fields amended with N fertilizers, animal manure, aquifers, sewage, industry, automobiles, biomass burning, land clearing, and trash incineration. The contribution of agriculture to the global N2O source is about 35 percent The Properties of Greenhouse Gases GHGs vary in their ability to absorb & hold heat in the atmosphere, a phenomenon known as the "greenhouse effect." HFCs & PFCs are the most heat-absorbent, but there are also wide differences between naturally occurring gases. For example, N2O absorbs 270 times more heat per molecule than CO2 & CH4 absorbs 21 times more heat per molecule than CO2 . Global warming and greenhouse effects Global warming is the rise in the average temperature of Earth's atmosphere and oceans since the late 19th century and its projected continuation. Since the early 20th century, Earth's mean surface temperature has increased by about 0.8 °C (1.4 °F), with about two-thirds of the increase occurring since 1980. Such global rise in temperature is due to effect of greenhouse gases, such as carbon dioxide emissions from burning fossil fuels or from deforestation, which trap heat that would otherwise escape from Earth. This is a type of greenhouse effect. Climate change and its causes Climate change is a long-term shift in weather conditions identified by changes in temperature, precipitation, winds, and other indicators. Climate change can involve both changes in average conditions and changes in variability, including, for example, extreme events. The earth's climate is naturally variable on all time scales. However, its long-term state and average temperature are regulated by the balance between incoming and outgoing energy, which determines the Earth's energy balance. Any factor that causes a sustained change to the amount of incoming energy or the amount of outgoing energy can lead to climate change. As these factors are external to the climate system, they are referred to as 'climate forcers', invoking the idea that they force or push the climate towards a new long-term state - either warmer or cooler depending on the cause of change. Different factors operate on different time scales, and not all of those factors that have been responsible for changes in earth's climate in the distant past are relevant to contemporary climate change. Factors that cause climate change can be divided natural causes and human causes. I. Natural Causes The Earth's climate can be affected by natural factors that are external to the climate system, such as changes in volcanic activity, solar output, and the short term cycles like El Nino. Of these, the two factors relevant on time scales of contemporary CC are changes in volcanic activity & changes in SR. In terms of the Earth's energy balance, these factors primarily influence the amount of incoming energy. Volcanic eruptions are episodic & have relatively short-term effects on climate. Volcanic eruptions like Mt. Pinatubo in 1991 inject sulfur dioxide into the upper atmosphere. Sulfur dioxide is highly reflective to the sunlight. Thus, its presence in the upper atmosphere, prevents a portion of the sun’s energy from reaching the earth. Once in the upper atmosphere, these compounds can exist for several years following the eruption. The amount of energy emitted by the sun is not constant. Changes in its intensity are typically small (a few tenths of a percent), but can influence temperature s on the Earth if they occur over an extended period of time. Short term cycles like El Nino: The oceans and atmosphere work together to influence climate. Natural oscillations in ocean currents, the location of the warmest or coldest ocean temperatures, etc. can influence atmospheric circulation patterns. El Nino is an example in this case the pool of the warm water that usually resides in the Western Tropical Pacific Ocean migrates east. This changes the atmospheric circulation pattern in the tropics which influences global weather pattern. ii. Human Causes It is this human-induced enhancement of the greenhouse effect that is of concern because ongoing emissions of GHGs have the potential to warm the planet to levels that have never been experienced in the history of human civilization. Such climate change could have far-reaching and/or unpredictable environmental, social, and economic consequences. Since the beginning of the Industrial Revolution, these human influences on the climate system have increased substantially. In addition to other environmental impacts, these activities change the land surface & emit various substances to the atmosphere. These in turn can influence both the amount of incoming energy & the amount of outgoing energy & can have both warming & cooling effects on the climate. Conc. of greenhouse gases in the atmosphere are much higher than they have been for the last 800,000 years. CC can also be caused by human activities, such as the o burning of fossil fuels & o the conversion of land for agriculture & urbanization o Agricultural activities 1. Burning of fossil fuels. Since industrialisation, GHGs conc. have increased dramatically. The major cause of this increase is the burning of fossil fuels.Fossil fuels are burned in following activities; o Generation of electricity (buring of coal & natural gages) o Transportation o Industry o Commercial and residential areas o Agriculture The dominant product of fossil fuel combustion is CO2, During the 150 years of the industrial age, the atmospheric concentration of CO2 has increased by 31%. The overall effect of human activities since the Industrial Revolution has been a warming effect, driven primarily by emissions of CO2 & enhanced by emissions of other greenhouse gases. 2. Deforestation Deforestation accounts for an additional 18 % of GHGs emissions. Deforestation influences the climate in two ways; Trees are sinks for atmospheric carbondioxide, they remove carbondioxide from the air and store it as vegetative matter (organic matter). Fewer trees mean less CO2 is pulled from the atmopshere. If these trees are burned, the CO2 is added back to the atmosphere. Removal of the trees changes the character of the land surface; this changes the amount of solar energy that is absorbed by the surface, evaporation. Generally, more thickly forested areas have lower albedos, so more shortwave energy falling on them is absorbed and less is reflected immediately back to the atmosphere. Urbanized areas and areas where trees have been clearc ut tend to have higher albedos 3. Urbanization Effect of urbanization is similar to deforestation. Urbanized areas and areas where trees have been clear cut tend to have higher albedos. Air in the urban areas tend to absorb and hold more heat than vegetative surface Thus cities are more warmer than rural environment. Urban area also emits enormous amount of GHGs through burning of fossil fuels. 4. Agricultural activities Since industrialization, level of atmospheric CH4 has risen by 151 %, mostly from ag. activities such as raising cattle & growing rice. Modern agriculture, food production & distribution are major contributors of greenhouse gases. Agriculture is directly responsible for 14% of total GHGs emissions, & broader rural land use decisions have an even larger impact. Over the last 150 years, 476 billions of tonnes of carbon has been emitted from farmland soils due to inappropriate farming & grazing practices, compared with ‘only’ 270 Gt emitted from of burning of fossil fuels. Fooded rice field is considered as chimney for CH4 emission. One cattle can emit as high as 120 kg methane per year (0.015 kg for chicken). Buring of the crop residues including cow dung emits significant amount of CO2 to the atmosphere. Use of fertilizers (such as nitrous oxide and pesticidies also contributes GHGs to the atmosphere. The contribution of agriculture to the global N2O source is about 35 percent. Expected effects of global warming on global agricultural production As the concentration of greenhouse gases grows, more heat is trapped in the atmosphere and less escapes back into space. This increase in trapped heat changes the climate and alters weather patterns, which may hasten species extinction, influence the length of seasons, cause coastal flooding, and lead to more frequent and severe storms. i. Soil processes The potential for soils to support agriculture and distribution of land use will be influenced by changes in soil water balance: It increases in soil water deficits i.e. dry soils become drier, therefore increased need for irrigation but Could improve soil workability in wetter regions and diminish poaching and erosion risk ii. Crops The effect of increased temperature and CO2 levels on arable crops will be broadly neutral: • The range of current crops will move northward • New crop varieties may need to be selected • Horticultural crops are more susceptible to changing conditions than arable crops; (what happens to the high chilling requiring temperature fruits such as apple???) • Field vegetables will be particularly affected by temperature changes • Phaselous bean, onion and sweet corn are most likely to benefit commercially from higher temperatures • Water deficits will directly affect fruit and vegetable production iii. Grasslands and livestock • There is unlikely to be a significant change in suitability of livestock. • Pigs and poultry could be exposed to higher incidences of heat stress, thus influencing productivity • Increase in disease transmission by faster growth rates of pathogens in the environment and more efficient and abundant vectors (such as insects) • Consequences for food quality and storage iv. Weeds, pests and diseases: • Weeds evolve rapidly to overcome control measures, short lived weeds and those that spread vegetative (creeping buttercup, couch etc.) evolve at the greatest rate: • Rate of evolution will increase in hotter, drier conditions and in 'extreme years', could lead to some types of herbicide tolerance becoming more common • Possible increase in the range of many native pests, and species that at present are not economically important may become so • Surveillance and eradication processes for other significant pests, such as the Colorado beetle will become increasingly important Impact of Agriculture on Climate change 1. Deforestation (for the expansion of agricultural land) releases CO2. 2. Intensification of irrigated paddy production which is considered as chimney of the CH4 emission. 3. Crop residue burnings releases green house gases. 4. Methane is released from enteric fermentation in coffee, nitrous oxide releases from fertilizer application. 64% of the global nitrous oxide emission is chiefly due to fertilizer application. 5. Intensification of the livestock production system (CH4 release) 6. Use of the modern equipment (e.g. tractor) that uses Fossil fuels releases CO2. Many of the following "harbingers" and "fingerprints" are now well under way: 1. Rising Seas--- inundation of fresh water marshlands (the everglades), low-lying cities, and islands with seawater. 2. Changes in rainfall patterns --- droughts and fires in some areas, flooding in other areas. See the section above on the recent droughts, for example! 3. Increased likelihood of extreme events--- such as flooding, hurricanes, etc. 4. Melting of the ice caps --- loss of habitat near the poles. Polar bears are now thought to be greatly endangered by the shortening of their feeding season due to dwindling ice packs. 5. Melting glaciers - significant melting of old glaciers is already observed. 6. Widespread vanishing of animal populations --- following widespread habitat loss. 7. Spread of disease --- migration of diseases such as malaria to new, now warmer, regions. 8. Bleaching of Coral Reefs due to warming seas and acidification due to carbonic acid formation --- One third of coral reefs now appear to have been severely damaged by warming seas. 9. Loss of Plankton due to warming seas --- The enormous (900 mile long) Aleution island ecosystems of orcas (killer whales), sea lions, sea otters, sea urchins, kelp beds, and fish populations, appears to have collapsed due to loss of plankton, leading to loss of sea lions, leading orcas to eat too many sea otters, leading to urchin explosions, leading to loss of kelp beds and their associated fish populations. |
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10 Comments
Hello Meena didi,
Hope you are doing great,
Thank you so much for your informative report,
Most of the climate change is due to human influence and its a sad reality,
Keep writing,
Green Cheers,
Bindu
Posted 18-07-2021 20:52
Hello meena
I hope you are doing well!
Nice report
Keep writing
Thank you so much for this report!
Looking forward to reading some more reports.
Green cheers!
Best regards
Hema
Posted 19-03-2020 11:40
Greetings meena
I hope you are doing well
Thank you so much for this great report
I hope to read more from you!
Green cheers
Regards
Ishma
Posted 17-03-2020 12:26
Hello meena
I hope you are doing well.
Thank you so much for this report.
Green cheers
Regards
Sus
Posted 07-03-2020 18:48
Hello meena
I hope you are doing well
Thank you so much for this report
Regards
Sus
Posted 01-03-2020 10:29
Greetings meena sis
I hope you are doing well !
Human influence in climate is clearly visible. It's very sad fact.
Thank you so much for this wonderful report.
Green cheers
Regards
Asmita Gaire
Posted 27-01-2020 15:49
Thank you TULA RAJ.
Posted 07-10-2019 15:48
Hello!!!
Thank you for such an informative piece of writing.
Yours,
TULA RAJ
Posted 07-10-2019 15:46
Thank you Sandhya!!!
Posted 07-10-2019 15:18
Hello meena pandey,
I do hope you are fine and doing great with your works,
This report is really so realistic that you had written addressing the current situations how human is deteriorating the ecosystem with their deeds,
Human has a great influence on the climate change, green house emission and so on.
Its our sole responsibility to work for this environment to cope up with every tousle.
Keep writing such representationalism report.
Looking forward to read much more from you.
GREEN CHEERS,
Yours,
Sandhya
Posted 06-10-2019 23:40