Basics of Climate Change

Climate Change

BASICS ABOUT GLOBAL WARMING AND CLIMATE CHANGE

• Climate : Long term pattern of weather.
• Climate change: The increasing temperature of earth due to green house effect is known as climate change. It is leading to extreme weather events,like melting of polar ice, rising sea levels, etc.

  

Factors affecting Climate Change :

Earth’s temperature is influenced by the energy entering and leaving the planet’s system. When incoming energy from the sun is absorbed by the Earth system, Earth is warmed. When the sun’s energy is reflected back into space, Earth cools. Both natural and anthropogenic factors can cause changes in Earth’s energy balance.

Natural Factors : The Earth’s climate can be affected by a number of natural factors. The prominent ones are continental drift, volcanoes, ocean currents, the earth’s tilt, and comets and meteorites. The natural factors affect climate change in the long term and persist for thousands to millions of years.

Continental Drift : The continents, what we are seeing today, were not alike 200 million years ago. It is formed when the landmass began gradually drifting apart millions of years back, due to Plate displacement. This drift also had an impact on the climate because it changed the physical features of the landmass, their position and the position of water bodies like changed the flow of ocean currents and winds, which affected the climate. The drift process is still continued today, the Himalayan range is rising by about 1 mm (millimetre) every year because the Indian land mass is moving towards the Asian landmass, slowly but steadily.

Variation in the earth’s orbit : The seasonal distribution of sunlight reaching the Earth’s surface is directly related to Earth’s Orbit and a slight variation in Earth’s orbit leads to variation in distribution across the globe. There are very little changes to the annually averaged sunshine; but there can be strong changes in the geographical and seasonal distribution. There are three types of orbital variations namely 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. The IPCC finding shows that Milankovitch cycles drove the ice age cycles.

Plate tectonics : Due to temperature variation in the core of the Earth, the mantle plumes and convection currents force the Plates of the Earth to adjust which causes the reconfiguration of the earth Plate. This can affect both global and local patterns of climate and atmosphere. The position of the continents also influences patterns of ocean circulation as it determines the geometry of the oceans. 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.

Volcanic activity : When the Volcano erupts, the outburst of gases and dust particles partially block the incoming rays of the Sun which lead to the cooling of the weather. Sulphur dioxide combines with the water to form tiny droplets of Sulphuric acid and these droplets are so small that many of them can stay aloft for several years. Although volcanic activity may last only a few days, large volumes of gases and ash can influence the climatic pattern over the several years.

Ocean currents : Ocean currents are the major component of the climatic system which is driven by the horizontal wind forces causing the displacement of the water against the sea surface. Due to temperature variation of the water, the climate of the region is largely influenced. 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 deep of water, and the long term redistribution of heat in the world’s ocean. Much of the heat that escapes from the oceans is in the form of water vapour, the most abundant greenhouse gases on the earth. Yet, water vapour also contributes to the formation of the clouds, which shade the surfaces and have a net cooling effect.

Anthropogenic (Human Caused) Factors: Anthropogenic or manmade factors result in short term climatic changes. It involves the changes in the energy balance of the Earth – atmosphere system leading to changes in weather and climate. Scientists have been observing a change in the climate since the beginning of the 20th Century that cannot be attributed to any of the ‘natural’ influences of the past. Global warming has occurred faster than any other climate change recorded by humans and so is of great interest and importance to the human population. Cause of anthropogenic (human caused) climate change includes greenhouse gases, aerosols and pattern of land use changes.

GREENHOUSE GASES (GHGS):

Gases in the earth’s atmosphere that trap heat are known as Greenhouse gases. They set sunlight pass through the atmosphere, but they prevent the heat that the sunlight brings from leaving the atmosphere. Greenhouse gases are crucial for survival of life on earth. In the absence of greenhouse gases, the average temperature on earth would have been- 18 degree Celsius instead of the present 15 degree Celsius.

As human activity has increased due to the onset of industrial revolution, the emission of huge amounts of GreenHouse Gases has also increased which led to more absorption of heat being retained in the atmosphere thus an increase in global Temperature. Greenhouse gases, while largely transparent to incoming solar radiation, absorb most of the infrared emitted by the earth’s surface.

Water Vapour :

It is the most important Greenhouse gas and plays an important role in controlling earth’s temperature. Water Vapours account for about 60% of the warming effect. The amount water in atmosphere rises with rising temperature and decreases with the fall in temperature. So, in a way it can be said that water vapour in the atmosphere is controlled by the temperature. But it is the non- condensable gases (mainly CO₂ which is bringing the increase in the temperature after the first industrial revolution) which are responsible for the recent rise in global warming.

Carbon-dioxide :

It is produced by burning of carbon-containing substances, mostly fuels (Coal, natural gas, oil). Solid waste trees, other biological materials etc.

Concentration of CO₂ in atmosphere : For the first time in human history, CO₂ in the atmosphere has crossed 415 ppm: according to sensors at the Mauna Loa Observatory, a research outpost of the National Oceanic and Atmospheric Agency (NOAA). (March 2020)  400 PPM (.4%) was once considered an unthinkable tipping point.

Methane :

Wetlands are the largest source of methane. They are also produced from growing rice, raising cattle, using natural gas and mining coal.

Reports : Global Methane Budget (July 2020) : The 2020 Global Methane budget shows that emissions of methane have hit the “highest level on record” in the year 2017 (the year for which full information is available) The annual global emission was 600m tones (i.e., 9% higher than the 2000-2006 average)

This increase is mainly attributable to anthropogenic factors : Agriculture (60%) and Fossil Fuels. (40%)

Nitrous Oxide :

It is the third most important GHG. It is long lived (average > 100 years), and has ozone depleting properties. It is a natural part of the nitrogen cycle. Bacteria in soil and the ocean make it. It is also produced during agricultural and industrial activities, combustion of fossil fuels and solid waste, as well as during treatment of wastewater.

Reports : Global Nitrous Oxide Budget :  N₂O is accumulating in the atmosphere at an increasing rate, with global emission of 17 Tg N in 2016. 10% greater than in the 1980s. Net emission (thus net addition) is 4.3 Tg. Main Anthropogenic factor is agriculture. Other factors include- fossil fuel, industry, waste and wastewater, and biomass burning.

Ozone :

Earth’s atmosphere has many layers, and each layer has its unique features. The ozone layer is a crucial part of the atmosphere. It is a part of the stratosphere (a layer of the atmosphere). The ozone layer works as a shield for the earth and reflects most of the UV rays produced by the sun. It protects the earth like an umbrella and interrupts harmful UV or ultraviolet rays to reach the earth’s surface. Therefore, the ozone layer also helps maintain the earth’s natural temperature. 

Global warming and ozone layer depletion :

• Global warming and ozone layer depletion are environmental phenomena that are closely intertwined. The term ozone hole means depletion in the ozone layer. This layer works as a protective layer of earth and helps absorb an excessive amount of UV rays, CFCs, Halon gas etc., that are harmful to living creatures of the earth. Depletion in the ozone layer can create various severe health problems.

• Increased Greenhouse gases, heat, pollution etc., are causing global warming and depletion of the ozone layer. Also, UV rays entering the earth’s atmosphere because of ozone layer depletion increases the temperature of the earth. So, both of these alarming environmental phenomena result from human activities like pollution, carbon release, deforestation, increased Greenhouse gases etc. 

Fluorinated Gases (HFCS, PFCS, SF6, Nitrogen Trifluoride (NF3) etc :

They are not naturally found in the atmosphere and are man made. Fluorinated gases are used as substitutes for ozone depleting substances like CFCs, HCFCs, and Halons Though they are released in small quantities, their global warming potential is very high.

Black Carbon :

It is the sooty black material emitted from gas and diesel engines, coal- fired power plants, and other sources that burn fossil fuel. It comprises a significant portion of particulate matter or PM, which is an air pollutant. It consists of pure carbon in several linked forms. It is a short- lived pollutant which is the key component of PM2.5. It has negative implications for our health and may cause respiratory and cardio- vascular diseases, cancer, birth defects and premature mortality.

NOTE: Short Lived Climate Pollutants (SLCP) are those pollutants that contribute to global warming but have a short lifetime (only a few days to 10 years). These include Black Carbon, Tropospheric Ozone, VOC, NO_x, Methane, and some HFCs.Black Carbon has small life and thus the impact can be reduced very soon after emissions are reduced.

 It is also responsible for climate change and has recently been recognized as second most important anthropogenic for climate change.Black Carbon deposits can accelerate the pace of glacier and snow melt in the Himalayan region. It reduces the reflective capacity of snow. It increases the air temperature.

It itself is a very good absorber of sunlight and heats the air directly. The fine particles absorb a million times more energy than CO_2. It is also responsible for affecting cloud formation and thus affects rainfall. A recent study has shown that it may also be depleting the ozone layer.

 Main sources: Incomplete burning fuel (i.e. inefficient burning environment) produces black carbon. Solid Fuel Burning (coal, biomass etc.) Industry (primary brick Kilns) and residential burning of solid fuel together account for about 45-66% of anthropogenic BC deposition in Himalayan region. Diesel exhausts contribute to 7- 18% black carbon deposits in the Himalayan region.

Since, India has a large population depending on bio- mass and solid fuel, it contributes to around 25% of the world’s Black Carbon Emission. According to a study published in the journal Atmospheric Research in April 2019, India is the 2^nd largest contributor to black carbon in the world.

 Steps taken by government to reduce black carbon :

• Enhancing fuel efficiency standards of vehicles, phasing out diesel vehicles and promoting electric vehicles.
• Promotion of the use of LPG for cooking. (PM Ujjwala Yojana)
• Clean cookstoves program.
• Upgrading brick kiln technologies
• Real time monitoring of black carbon aerosols in the Glaciated Valley of northwestern Indian Himalayas.

However, with all existing measures, water from glacier melt is still projected to increase in absolute volume by 2040, with impact on downstream activities and communities.

 According to a study by Wadia Institute of Himalayan Geology, Dehradun, Black Carbon Concentration near Gangotri Glacier rose 400 times in summer due to forest fires, stubble burning from agri- waste, and triggered glacier melt. (March 2020).

 Brown Carbon :

Brown Carbon is emitted mainly by biomass combustion. It is a light absorbing part of the organic aerosol (note: soot is also light absorbing in nature). In recent years it has come under a lot of research. It absorbs strongly in the ultraviolet wavelength (high frequency) and less significance into the visible (low frequency).

Sources of Brown Carbon :

• Tar Material from smouldering fires or coal combustion.
• Breakdown products from biomass burning, stubble burning.
• A mixture of organic compounds emitted from soil, and volatile organic compounds given off by vegetation.

Primary Brown Carbon vs Secondary Brown Carbon

• Black carbon is primarily produced by high temperature combustion and brown carbon is emitted mainly by biomass combustion.
• Of the total atmospheric absorption by aerosol, brown carbon contributes about 19% while 72% is contributed by black carbon. The remaining 9% is due to the coating effect of sulphate and organic aerosols on black carbon.

Both are two most important light absorbing substances in the atmosphere.

 Tarballs and its implications : Tarballs are formed from brown carbon. They are small light absorbing, carbonaceous particles formed due to burning of fossil fuels that deposit on snow and ice.

Recent research has shown that tarballs from long- range transport can be an important factor in the climatic effect of glacier melting in the Himalayas. Nearly 28% of particles collected from the air samples from a research station in Himalayan- Tibetan Plateau were tarballs.

Atmospheric Aerosols:

Atmospheric aerosols affect climate in two important ways:

• They cause scattering and absorption of solar and infrared radiation.
• They change the microphysical and chemical properties of clouds and possibly their lifetime and extent.

The scattering of solar radiation cools the planet, while absorption of solar radiation by aerosols acts to warm the air directly instead of allowing sunlight to be absorbed by the surface of the Earth. Aerosols have the ability to influence climate directly by absorbing or reflecting incoming solar radiation, but they can also produce indirect effects on climate by modifying cloud formation or cloud properties. Aerosols can be transported thousands of kilometres from the sources of origin by winds and upper level circulation in the atmosphere.

There are two types of aerosols:

Natural Aerosols : These forms of aerosols include windblown mineral dust generated in arid and semiarid regions. Other natural sources of aerosols include volcanic eruptions, which produces sulphate aerosols and biogenic sources (e.g. Phytoplankton) which produce dimethyl sulphide. Other important biogenic aerosols such as terpenes are produced naturally by certain kinds of trees or other plants.

Anthropogenic Aerosols: Human activity has increased the amount of aerosols in the atmosphere in several ways. Ammonia which is often used in Fertilisers or released by the burning of plants and other organic materials is the prominent source of Nitrate aerosols. The burning of coal and oil produces sulphur dioxide which is another major source of sulphate aerosols. Dust is often a bi-product of agricultural processes.

Biomass burning releases a combination of organic droplets and soot particles. Industrial processes release a wide variety of aerosols. Exhaust emissions from transport generate a rich cocktail of pollutants that are either aerosols from the outset, or are converted by chemical reactions in the atmosphere to form aerosols. The concentrations of aerosols are about three times higher in the Northern Hemisphere than in the Southern Hemisphere. This higher concentration is estimated to result in radiation forcing that is about 50 per cent higher for the Northern Hemisphere.

Impacts of Climate Change

Rising global temperature is accompanied by the changes in weather and climate like changes in rainfall, resulting in more floods, droughts, or intense rain, as well as more frequent and severe heat waves. The planet’s oceans and glaciers have also experienced some big changes – oceans are warming and becoming more acidic, ice caps are melting, and sea levels are rising.  As these changes become more pronounced in the coming decades, they pose a great challenge to our society and our environment.

Higher Temperatures : GreenHouse gases released by power plants, automobiles, deforestation and other sources are heating up the planet. In fact, the five hottest years on record have all occurred since 1997 and the 10 hottest since 1990, including the warmest years on record – 2005 and 2010.

Increased temperatures are to blame for an increase in heat-related deaths and illness, rising seas, increased storm intensity, and many of the other dangerous consequences of climate change. During the 20th century, the Earth’s average temperature has increased by one degree Fahrenheit to its highest level in the past four centuries – believed to be the fastest rise in a thousand years. Research found that if emissions of heat-trapping carbon emissions aren’t reduced, average surface temperatures could increase by 3 to 10 degrees Fahrenheit by the end of the century.

Changing Landscapes: Increasing temperatures and changing patterns of rain and snow have resulted in moving of trees and plants around the world toward Polar Regions and up mountain slopes.

These vegetation shifts will affect much of the work the conservation community has accomplished to date, with the potential to permanently change the face of Conservancy preserves, local land trusts, and even our national parks. As plant communities try to adapt to the changing climate by moving toward cooler areas, the animals that depend on them will be forced to move in order to survive. Some species and communities such as polar bears and alpine meadows may be left without any remaining viable habitat, putting much of our treasured wildlife at risk.

 Wildlife / Ecosystem at Risk: Increased temperatures are changing weather and vegetation patterns across the globe, forcing animal species to migrate to new, cooler areas in order to survive. The rapid change of climate change is likely to exceed the ability of many species to migrate or adjust. Experts predict that one-fourth of Earth’s species will be headed for extinction by 2050 if the warming trend continues at its current rate.

 Many species are already feeling the heat :  In 1999, the death of the last Golden Toad in Central America marked the first documented species extinction driven by climate change.  Due to melting ice in the Arctic, polar bears may be gone from the planet in as little as 100 years. In the tropics, rising sea temperatures are causing more coral reefs to “bleach,” as the heat kills colourful algae that are necessary to coral health and survival.

 Ocean Acidification /Rising Seas level : As the Earth heats up, sea levels rise up because warmer water takes up more area than colder water, a process known as thermal expansion. Melting glaciers compound the problem by dumping even more fresh water into the oceans.

Rising seas threaten the populated low-lying areas, islands and dense coastal populations, erode shorelines, damage property and destroy ecosystems such as mangroves and wetlands that protect coasts against storms.

Sea levels have risen between four and eight inches in the past 100 years. Current projections suggest that sea levels could continue to rise between 4 inches and 36 inches over the next 100 years.

The increased concentration of carbon dioxide (CO2) in the atmosphere has increased the absorption of CO2 in the ocean, which reduces the pH and makes the oceans more acidic.

A more acidic ocean would adversely affect the health of many marine species, including plankton, molluscs, and other shellfish. In particular, corals can be very sensitive to rising acidity, as it is difficult for them to create and maintain the skeletal structures needed for their support and protection.

 Increased Risk of Drought, Fire and Floods : Higher temperatures increase the amount of moisture that evaporates from land and water, leading to drought in many areas. Lands affected by drought are more vulnerable to flooding once rain falls.

As temperatures rise globally, droughts will become more frequent and more severe, with potentially devastating consequences for agriculture, water supply and human health. This phenomenon has already been observed in some parts of Asia and Africa, where droughts have become longer and more intense. Hot temperatures and dry conditions also increase the likelihood of forest fires.

 Intensified Storms and Increased Storm Damages : Scientific research indicates that climate change will cause hurricanes and tropical storms to become more intense — lasting longer, unleashing stronger winds, and causing more damage to coastal ecosystems and communities. Higher ocean temperatures is the main culprit, since hurricanes and tropical storms get their energy from warm water. As sea surface temperatures rise, developing storms will contain more energy.

At the same time, other factors such as rising sea levels, disappearing wetlands, and increased coastal development threaten to intensify the damage caused by hurricanes and tropical storms.

Illness and Disease: As temperatures increase, so do the risks of heat-related illness and even death for the most vulnerable human populations. Scientists have linked the deadly heat waves to climate change and warn of more to come.  In 2003, for example, extreme heat waves caused more than 20,000 deaths in Europe and more than 1,500 deaths in India.

Climate change increases the spread of infectious diseases, mainly because warmer temperatures allow disease-carrying insects, animals and microbes to survive in areas where they were once blocked by cold weather. Diseases and pests that were once limited to the tropics — such as mosquitoes that carry malaria — may find hospitable conditions in new areas that were once too cold to support them.

The World Health Organization (WHO) estimates that climate change may have caused more than 150,000 deaths in the year 2000 alone, with an increase in deaths likely in the future.

Economic Losses : Research says that if no action is taken to curtail global carbon emissions, climate change could cost between 5 and 20 percent of the annual global gross domestic product. In comparison, it would take 1 percent of GDP to lessen the most damaging effects of climate change.

Climate change may significantly lower lake levels, altering shoreline habitats and costing millions for the relocation of ports and shore infrastructure. Globally, more intense hurricanes and downpours could cause billions of dollars in damage to property and infrastructure. Declining crop yields due to prolonged drought and high temperatures, especially in Africa, could put hundreds of thousands of people at risk for starvation. High sea temperatures also threaten the survival of coral reefs, which generate an estimated $375 billion per year in goods and services.

 Agriculture Productivity/Food Security : Solar radiation, temperature, and precipitation are the essential drivers of crop growth; therefore agriculture has always been highly dependent on climate patterns and variations.Since the industrial revolution, humans have been changing the global climate by emitting huge amounts of greenhouse gases into the atmosphere, resulting in higher global temperatures, affecting hydrological regimes and increasing climatic variability.

Climate change is projected to have significant impacts on agricultural conditions, food supply, and food security. Some of these effects are biophysical, some are ecological, and some are economic, including:

• A shift in climate and agricultural zones towards the poles .
• Changes in production patterns due to higher temperatures.
• A boost in agricultural productivity due to increased carbon dioxide in the atmosphere.
• Changing precipitation patterns.
• Increased vulnerability of the landless and the poor.

SUSTAINABLE DEVELOPMENT GOALS AND CLIMATE CHANGE

Goal 13 : Climate Action

Targets :

• Strengthen resilience and adaptive capacity to climate- related hazards and natural disasters in all countries.
• Integrate climate change measures into national policies, strategies and planning.
• Improve education, awareness- raising and human and institutional capacity on climate change mitigation, adaptation, impact reduction and early warning.
• Implement the commitment undertaken by developed- country parties to the United Nations Framework Convention on Climate change to a goal of mobilising jointly $100 billion annually by 2020 from all sources to address the needs developing countries in the context of meaningful mitigation actions and transparency on implementation and fully operationalize the green climate fund through its capitalization as soon as possible.
• Promote mechanisms for raising capacity for effective climate change related planning and management in least developed countries and small island developing states including focusing on women, youth and local and marginalised communities.