What is Climate Change? Causes, Environmental Impact and Climate Action Strategies


What is Climate Change? Causes, Environmental Impact and Climate Action Strategies

Climate change has been a part of Earth’s geological history. This indicates that the mean annual temperature of the planet has increased and decreased by several degree Celsius over the past million years. Times when temperatures have been relatively lower are called as glacial periods and higher temperatures correspond to interglacial periods. 

As per World Meteorological Organization (WMO). ‘“ Climate Change refers to a significant variation in mean state of climate (in temperature, winds, precipitation etc.) for an extended period of time (usually 10 years or longer) ‘’. 

 On the other side, Global Warming is a closely related concept to climate change. It is defined as increase in the global mean surface temperature of near-surface atmosphere and oceans averaged over a 30-year period. It is often used interchangeably with climate change but is to be differentiated from it. Climate change is about all types of climatic variability over the planet, whereas, global warming is with respect to global mean surface temperature only. 

Causes for Climate Change:-

 1. Greenhouse Effect:

The greenhouse effect is one of the important issues and is one which humankind has the capacity to change for the improvement of our environment.

As we all know most of the solar radiation which reaches the Earth is of relatively short wavelength- that is in the infrared and visible wavelength. Whereas, the energy radiated back by the warmed earth is relatively long-wave radiation.

Shortwave radiation can pass easily through the atmosphere, whereas longwave terrestrial radiation from the warm surface of the Earth is partially absorbed by a number of trace gases in the atmosphere. These trace gases are called greenhouse gases. The main natural Greenhouse gases are Carbon dioxide, Methane, nitrous oxide, water vapour and ozone in the troposphere and stratosphere. Further, human activities in recent decades are adding new halocarbons as a greenhouse gas.

Thus the greenhouse effect arises because the atmosphere is largely transparent to incoming solar radiation. Also, greenhouse gases heavily absorb the outgoing thermal radiation from the planetary surface and the atmosphere. Since the beginning of the universe, the effect exists as a natural process. But since the twentieth century, the effect is enhanced by man’s activities that are liable to destabilize the natural balance. Different trace gases in the atmosphere contribute to the greenhouse effect, but among them are four major gases, carbon dioxide, chlorofluorocarbons, methane and oxides of nitrogen. 

The greenhouse Effect is a natural phenomenon and ensures moderate temperature for life to exist over the planet.  

2. Major human activities driving climate change are

  • Burning of fossil fuels - 

Increased atmospheric concentration of Greenhouse gases due to the burning of fossil fuels is the major driver of climate change. The major sources of Greenhouse gases are- Industrial emissions of carbon dioxide from thermal power plants; vehicular emissions of carbon dioxide and Nitrogen oxide agriculture activities-based emissions like Methane and Nitrous Oxide.  

  • Shrinking carbon sinks and changes in land use -

Forests, peatlands, mangrove forests, seagrass meadows, kelp forests etc. and other land and water-based natural ecosystems act as carbon sinks. The process of absorption of carbon in a sink for long-term storage is called Carbon Sequestration. For example, the process of photosynthesis by forests is biological C- Sequestration. 

            The natural ecosystems which have long acted as carbon sinks are being lost or degraded at a fast rate. For example - almost 20% of Amazon rainforests disappeared in the last 50 years. As per WMO, some major ecosystems are being lost at a rate of up to 3% per annum. When degraded, these ecosystems emit the carbon they have stored for centuries and thus become sources of GHGs.

Why and how has the Carbon dioxide Concentration in the Atmosphere been Increasing?

By burning large amounts of fossil fuels, we release huge quantities by carbon dioxide into the atmosphere. Concurrently, deforestation also releases carbon trapped in the tissues of the trees. At the same time, the loss of trees reduces the earth’s capacity to absorb carbon dioxide through photosynthesis. Natural processes like volcano eruptions and earthquake-induced fires also contribute to carbon dioxide emissions. Due to these factors, the carbon dioxide concentration in the atmosphere has been rapidly increasing.

Some of the other greenhouse gases are far more effective than carbon dioxide in trapping heat. Chlorofluorocarbons(CFCs) are an example, but their role is greater in the depletion of the ozone layer. Methane, released from swamps, garbage dumps, and human and animal waste is also a greenhouse gas and its concentration is increasing. Similarly, human activities are causing a rapid increase in the amounts of thirty other greenhouse gases. 

As per NASA report, CFCs rise is about 5 per cent per year, while methane rise is about 1 per cent per year. On the whole, if the rise of greenhouse gasses takes place at the current rate, the overall rise of each pollutant gas that contributes to the greenhouse effect will double sometime in 2030. It was shown that temperature change from 1850 to 2050 would be at the magnitude of 0.25°C to 3.5°C. The current rate of greenhouse gas emissions has to be restricted with utmost urgency.

Why then are we focusing on carbon dioxide emissions?

There are two main reasons why carbon dioxide gets all the attention:

  • Carbon dioxide has caused most of the warming since 1750. The other greenhouse gases are far less abundant in the atmosphere and are also being added more slowly.
  • Carbon dioxide remains in the atmosphere for hundreds or even thousands of years - longer than the other major greenhouse gases emitted as a result of human activities. The emissions that we release today from our cars and power plants will decide the climate for our children, grandchildren, and later generation 

 Role of  IPCC Assessment on Climate Change 

 World Meteorological Organization is a specialized agency of the United Nations. It is dedicated to international cooperation and coordination on the state and behaviour of the earth’s weather and climate. As per the State of Global Climate Report, 2018 (released by the World Meteorological Organization annually in the month of March of the subsequent year);

Globally 14 of the 15 warmest years on record have occurred in the twenty-first century.

2018 was the fourth warmest year on record. The past four years - 2015, 2016, 2017 and 2018 -have been amongst the four warmest years on record. This suggests that the long-term warming trend continues over the planet. 

Like World Meteorological Organization, there is another United Nations body for assessing science related to climate change. It is the Inter-governmental Panel on Climate Change (IPCC). It was created in 1988 by the joint efforts of World Meteorological Organization and United Nations Environment Programme (UNEP). 

It provides governments across the world with scientific information for framing policies for climate change. IPCC produces periodic reports called Assessment Reports. Till now six Assessment Reports have been produced. 

Inter-governmental Panel on Climate Change Special Report 1.5°C observes that ‘human activities have caused approximately 1°C of global warming above pre-industrial levels’. 

What is the Current Impact of Climate Change?

Climate change is already here and is set to become worse. The impact is and will be widespread and long-lasting: 

1. Natural disasters 

There were an unprecedented number of natural disasters during the 1990s and that trend continues in the twenty-first century. Direct and insured losses from weather-related disasters have increased substantially in recent decades, both globally and regionally. As per IPCC 1.5°C Special Report (2018) and the World Meteorological Organization at the present levels of warming, the frequency and intensity of extreme weather events like heat waves, droughts, intense precipitation causing floods, tropical cyclones, cold waves etc. have already increased. The abnormal weather events which were ‘once in a century’ events are getting more frequent.2019 was again a year of such weather extremities with heatwaves in Europe; wildfires in Australia and the Arctic, deadly tropical cyclones in Japan, India; erratic rainfall in many parts of the world including India.

2. Ocean and Coasts

The ocean has become warmer and more acidic and sea levels are rising. The melting of polar ice caps is adding to the problem. Small islands like those of the Maldives, South Pacific, and Sundarbans are threatened. If sea levels continue to rise, coastal areas will be flooded in places like the Netherlands, Egypt, Bangladesh, and Indonesia, necessitating the evacuation of large populations.

Coral reefs are already dying all over the world due to human activities. A warmer and more acidic ocean will accelerate this process. Corals are home to 9 million different kinds of marine plants and animals. Their death will have a devastating effect on marine life and fisheries. 

3. Deoxygenation of Open Oceans 

As the solubility of oxygen decreases in warmer waters, it is causing deoxygenation of open oceans. Since the 1950s, there has been an estimated 12% decrease in global ocean oxygen inventory.

4. Melting of glaciers, ice caps, and permafrost 

 Glaciers continue to shrink worldwide, Permafrost is warming and thawing in high-latitude regions and in high-elevation regions. The most dramatic evidence of this change is the melting of the Arctic. 

5. Ecological Degradation and Loss of Biodiversity 

Decline in the functioning of ecosystems is called as ecological degradation. Climate change is altering ecosystems across the globe. Forest degradation and forest fires, land degradation, and coral bleaching are some prominent examples.

Many species are facing enhanced stresses due to changing geographic ranges and habitats due to climate change. For example, Arctic species like polar bears are threatened due to shrinking ice cover. In 2019, the Australian government officially declared that the Australian island mammal, Bramble Cay Melomy, became the first ever mammal to go extinct due to climate change.

6. Water, agriculture, and food  

In many regions, changing precipitation or melting snow and ice are altering hydrological systems, affecting water resources in terms of quantity and quality. The negative impacts of climate change on crop yields have been more common than positive impacts. 

Extreme floods and droughts are likely to have serious effects on water resources, agriculture, and food security: 

  • Loss of topsoil, erosion of soil, and desertification 
  • Overflow of sewage systems and resulting water pollution and epidemics 
  • Amount and location of fresh water affected by changing rainfall, melting ice, and more evaporation ( For example, if the Himalayan glaciers are gone, there will be no water for 500 million people.) 
  • Warmer water attracts more organisms and gets contaminated 
  • Sea-level rise bringing salt water into coastal marshes and aquifers 

7. Animals, Plant species, and human beings  

Many terrestrial, freshwater, and marine species have shifted their geographic ranges, seasonal activities, migration patterns, abundances, and species interaction in response to climate change.

Thousands of animal and plant species will go extinct, unable to adjust quickly enough to the new conditions. Polar species may be the first to go, followed by those in the coastal zones everywhere. 

Warming will increase photosynthesis activity leading to faster growth of plants and trees. Initially, the yields will be more, but too much heat will kill the crops.

Extreme weather will increase human migration. There will be many millions more environmental refugees. People living on the coasts will suffer extensive damage due to sea-level rise and cyclones.  

What should the World Community do about Climate Change? 

 Mitigation and Adaptation are complementary strategies for reducing and managing the risks of climate change: 


It refers to human actions to reduce Greenhouse Gas emissions or enhance the sinks of greenhouse Gases. It includes the following: 

1. Burn less fossil fuel so that we emit less carbon dioxide. Technological improvements and lifestyle changes can reduce the amount of energy we use on transportation, heating, appliances that run on electricity, industrial production and so on. Alternative energy resources such as wind, solar, hydro, and biomass power should be exploited

2. Afforestation as forests act as carbon reservoirs through photosynthesis 

3. Garbage dumps (landfills) release methane from rotting organic waste. By capturing this gas and using it as fuel, we get both heat and reduced emissions of greenhouse gases.

4. C - Sequestration -Carbon sequestration is the process involved in carbon capture and the long-term storage of atmospheric carbon dioxide. It can be done in the following ways: 

  • Afforestation
  • Wetland Restoration
  • Sustainable Agriculture
  • Growing seaweed that can be used to produce bio-methane
  • Biochar is produced by pyrolysis of biowaste. It can be used as a landfill and increase soil fertility.
  • Subterranean injection involves injecting carbon dioxide into depleted oil and gas reservoirs and other geological features, or into the deep ocean. 
  • Iron fertilization of Oceans encourages the growth of plankton and thus captures carbon dioxide. 

Adaptation: - 

It refers to making adjustments to the effects of climate change so as to minimize the harmful impacts on human systems and lives. A few of the adaptation strategies include: 

  • Robust disaster management to reduce loss of human lives and assets due to climate-induced hazards. 
  • Climate Smart Agriculture (CSA) - As per FAO, climate-smart agriculture has three main objectives- sustainably increasing agricultural productivity and incomes; adapting and building resilience to climate change; and reducing greenhouse gas emissions. In CSA, the reorientation of agricultural systems is done as per changing climate. The ultimate objective is to ensure food security.

As climate change will exacerbate water stresses due to droughts, improving water use efficiency in agriculture becomes critical. It can be done through precision- irrigation techniques like drip or sprinkler irrigation.  

Geo-Engineering:- It is a large-scale intervention in the Earth’s climatic system with the aim of limiting climate change. Theoretically, there are two major types of interventions - Carbon Sequestration and Solar radiation management. Solar Radiation Management techniques include firing sulphur dioxide into the atmosphere, putting huge mirrors in the space, and creating pale-coloured rooftops and other structures which have a high albedo.

What is the International Initiative for Tackling Climate Change? 

Climate change is obviously the most urgent issue that calls for an international agreement. All the countries are affected by it and most countries contribute to the worsening situation. Yet, the world community has been unable to agree on emission reductions. 

The early Inter-governmental Panel on Climate Change (IPCC) reports spurred governments to create the UN Framework Convention on Climate Change (UNFCCC), which came into force in 1994. The convention sets an overall framework for intergovernmental efforts to tackle the challenges posed by climate change. It recognizes that the climate system is a shared resource whose stability can be affected by industrial and other emissions of carbon dioxide and other greenhouse gases. 

IPCC reports are used as the basis for decisions made under the UNFCCC, and they played a major role in the negotiations leading to the Kyoto Protocol. 

 What is Kyoto Protocol?

The Kyoto Protocol was an international agreement to reduce greenhouse gas emissions. It was negotiated under the UN Framework Convention on Climate Cange (UNFCCC) during a meeting held in Kyoto, Japan, in 1997. 

It was a legally binding agreement under which industrialized countries were to reduce their collective emissions of greenhouse gases by 5.2 per cent compared to the year 1990. Developing countries were not legally bound to emissions reduction targets initially, because these countries had historically been responsible for only a small portion of the global greenhouse gas emissions.

Under the protocol, countries were to meet their targets primarily through national measures. 

Salient features of the Kyoto Protocol (KP) of UNFCCC: 

  • It committed to developed countries by setting internationally binding emission reduction targets for them. The legally binding targets were set only for developed countries as they were historically responsible for emissions since the industrial revolution. None of the developing countries had very significant emissions back in the 1990s. 

  • The aim of KP was to reduce Greenhouse gas emissions by an average of 5% compared to 1990 levels over the five-year commitment period from 2008 to 2012. Therefore, 2008 to 2012 was called the first commitment period of the Kyoto Protocol.
  • Each developed country had its own individual emissions target. 
  • The maximum amount of emissions (measured are equivalent to carbon dioxide) that a party May emit over the commitment period in order to comply with its emissions target is known as the Assigned Amount Units. These are measured as 1 ton of carbon dioxide equivalent. 
  • Kyoto Protocol covered emissions from 6 main greenhouse gases:

 Carbon dioxide, Methane, Nitrous oxide, Hydrofluorocarbons, Perfluorocarbons and
Sulphur Hexa Fluoride
  • The protocol also offered them an additional means to meet their targets by way of market-based mechanisms: 

 International Emissions Trading: This mechanism allowed countries that had emission units to spare emissions permitted them but not ‘used’ to sell this excess capacity to countries that were over their targets. Thus, a new commodity was created in the form of emission reductions. Since carbon dioxide is the principal Greenhouse gas, people speak simply of trading in carbon. Carbon is now tracked and traded like any other commodity. This is known as the ‘carbon market’ 

 Clean Development Mechanism: This mechanism allows a country with an emission-reduction commitment to implement an emission-reduction project in developing countries. Such a project could earn saleable ‘carbon credits’ or emission reduction credits, each equivalent to 1 tonne of carbon dioxide, which can be counted towards meeting Kyoto targets.

Many countries including India ratified the Protocol. Most countries, however, did not meet the targets for emission reductions. Hence, the protocol’s impact on the rising trend in global emissions was very small. Even if the Protocol had been fully implemented, the small reduction in emissions would have done little to contain climate change.

The developed countries did not abide by their commitments under the Kyoto Protocol and therefore KP was unsuccessful in achieving its aim.  

FAQs on Climate Change 

Q.  What is Climate Change? 

Answer: It refers to a significant variation in the mean state of climate (in temperature, winds, precipitation etc.) for an extended period of time (usually 10 years or longer) 

Q. What is Black Carbon?

Answer: It is a short-lived climate pollutant that is produced due to incomplete combustion of fossil fuels. 

Q. What is Carbon Market? 

Answer - It is a market system that allows countries or industries, to earn carbon credits for emission reductions they make in excess of what is required of them (initially under the Kyoto Protocol). 

Q. What is Blue Carbon?

Answer - It refers to carbon stored, sequestered and cycled through coastal and ocean ecosystems like mangroves, tidal salt marshes and seagrass meadows. 

Q. What is Climate Finance? 

Answer - It refers to money from both public and private sources provided to developing countries and Least Developed Countries for their climate action efforts.

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