Global Warming

The phenomenon of rising average air temperatures close to the surface of the Earth over the previous one to two centuries is known as global warming. Since the middle of the 20th century, climate scientists have accumulated extensive data on a variety of weather events, including temperatures, precipitation, and storms, as well as on factors that have an impact on climates, such as ocean currents and the chemical makeup of the atmosphere. These findings show that Earth's climate has changed on practically every possible period since the beginning of geologic time and that human activities have increasingly affected the pace and scope of current climate change since the beginning of the Industrial Revolution.

Causes of Global Warming

Green House Effect

The Earth's average surface temperature is maintained through maintaining a balance between various forms of solar and terrestrial radiation. Solar radiation is frequently referred to as a ``shortwave" radiation because of its extraordinarily high frequencies and short wavelengths, which are close to the visible portion of the electromagnetic spectrum. Terrestrial radiation, on the other hand, is frequently referred to as "longwave" radiation due to the comparatively low frequencies and lengthy wavelengths—somewhere in the infrared region of the spectrum. Downward-moving solar energy is often measured in terms of Watts per square metre. At the top of the Earth's atmosphere, the "solar constant," or total solar radiation energy, is around 1,366 watts per square metre each year. The average annual surface insolation is 342 watts per square metre accounting for the fact that only 50% of the planet's surface is exposed to solar radiation.

The greenhouse effect adds to the complexity of Earth's energy balance. The so-called greenhouse gases, primarily carbon dioxide (CO₂), methane (CH₄), and nitrous oxide (N₂O), are trace gases with certain chemical properties that absorb some of the infrared light emitted by the Earth's surface. A portion of the original 70 units do not directly escape to space because of this absorption. The net result of absorption by greenhouse gases is to increase the total amount of radiation emitted downward toward Earth's surface and lower atmosphere because greenhouse gases emit the due to the radiation's uniform distribution and the fact that they absorb the same amount of it in all directions (that is, as much downward as upward).

Radiative Forcing

The temperature of the Earth's surface and lower atmosphere can be changed in three different ways, according to the greenhouse effect discussion above: (1) by a net increase in the solar radiation entering at the top of Earth's atmosphere, (2) by a change in the fraction of radiation reaching the surface, and (3) by a change in the concentration of greenhouse gases in the atmosphere. Changes in any situation can be explained by "radiative forcing."

Influence Of Human Activity On Climate

By altering the ozone and aerosol concentrations as well as the surface of the Earth's land cover, humans also have an impact on the climate. Such as

• Greenhouse Gases: emitting gases increase the amount of net downward longwave radiation that reaches the surface to warm the Earth's surface.

• Water Vapor: it does not have a direct impact on global warming but causes climate change. As surface temperature rises, the rate of water evaporation from a surface increases. A higher quantity of water vapour, which can absorb longwave radiation and emit it downward, can be found in the lower atmosphere because of enhanced evaporation.

• Carbon Dioxide: it has been produced by various sources from plants to animals Since the start of the industrial age, anthropogenic CO₂ emissions have caused an average radiative forcing of 1.66 watts per square metre.

• Methane: The second-most significant greenhouse gas is methane (CH₄). Along with the Pleistocene ice age cycles, methane concentrations have also changed across a smaller range (between roughly 350 and 800 ppb) (see Natural influences on climate). Anthropogenic CH₄ emissions have a net radiative forcing of around 0.5 watt per square metre, or about one-third that of CO₂.

• Surface Level Ozone and Other Compounds: Surface, or low-level, ozone is the second-largest greenhouse gas (O₃). Air pollution is the cause of surface O₃. The best estimates place the natural surface O3 content at 10 ppb, while the net radiative forcing brought on by anthropogenic surface O₃ emissions is roughly 0.35 watts per square metre. In cities that are prone to photochemical smog, ozone concentrations can approach harmful levels (conditions when concentrations meet or exceed 70 ppb for eight hours or longer).

Causes of Climate Change:

Under this head, the causes can be divided into two factors;

1. Manmade

2. Natural.

Global Warming: Is it a human-made cause?

• Higher Levels of Deforestation:

Deforestation affects the release of aerosols and other chemical compounds that affect clouds and changes in wind patterns, causing a flux in precipitation levels. In basic terms, Trees and plants are responsible for being the primary source of oxygen. By taking the carbon dioxide in, they release oxygen in the air, thereby maintaining a state of ecological balance, causing lesser air pollution. Planned human activities like continued forest loss for industrial and commercial motives drive the increase in carbon dioxide concentrations. As we know, Carbon dioxide is one of the leading heat-trapping gases, mainly responsible for average warming and environmental imbalance over the past few decades.

• Transportation and Use of Vehicles:

In this fast-paced world, people often use vehicles even for covering short distances. Gaseous emissions from cars and vehicles often drive temperature rise by trapping energy, which translates into heat. Such activities come under 'anthropogenic forcing,' i.e., human-influenced forces on the climate system. Continued transportation around congested areas contributes to air pollution, which eventually leads to increased global warming. According to IPCC reports, the transportation sector's contribution has grown by more than 50% since 1992 and continues to be one of the leading causes of global warming.

• Emissions of Chlorofluorocarbons:

In today's state of successive climate imbalance and issues of global warming, we all know that human-made causes have very high tendencies towards rising global surface temperatures. Other factors that add up to the causes are widespread commercialization and increased use of technological appliances such as Air conditioners and refrigerators. The atmospheric ozone layer is responsible for protecting the Earth's temperature from the sun's harmful UV radiation. Such practices have added an extra layer of CFCs or Chlorofluorocarbons in the air, depleting the intensity of the ozone layer.

• Emissions From Industries and Power Plants:

According to a report stated in 2018, some of the significant global anthropogenic greenhouse gas emissions are almost equal to 52 billion tonnes of Carbon dioxide. Out of which 72% is released from industries and power plants. With the advent of industrialization, the rising usage of electricity and heat, global warming has increased to a great extent. The release of pollutants from these sources has a significant impact on the environment and disturbs the delicate balance of nature.

• Agriculture and Land Surface Changes:

Frequent practices of agriculture take up almost 50% of the world's habitable land. Short term agricultural cultivation affects nearly 24% of the permanent land-use change. These activities also add up to the rise in temperature and GHG emissions from the land surface. The changes in land surface disturb the natural process of carbon storage and affect the reflection and absorption of sunlight heat. Soil erosion, Deforestation, and chemical fertilizers application lead to increased runoff that carries pollutants into water resources and eventually to the oceans.

• Combustion of Fossil Fuels, Overpopulation:

Most of the heat-trapping emissions from burning coal, gas, and oil from industries and cars, along with widespread Deforestation and rising levels of black carbon pollution or 'soot' in the form of aerosols affecting Earth's albedo come under this type. Also, the primary gas causing Global warming is Carbon dioxide, which is influenced by rising overpopulation.

Natural Causes of Global Warming

1. Volcanic Eruptions: They constitute one of the significant natural causes affecting global warming because of the increased release of gases and smoke from the eruptions.

2. Natural Forest Fires: When significant scale vegetation burns, leading to forest blaze, there is a release of stored carbon and a rise in greenhouse gas emissions. These emissions further trap solar energy leading to Global warming.

3. Melting Permafrost and Glaciers: Towards the north and south poles of the planet, considerably large amounts of carbon are frozen in the form of permafrost. Disturbances such as solar activities, forest fires, volcanic eruptions can lead to the sudden release of GHGs and carbon sequestration into the atmosphere, giving way to ecological imbalances.

4. Solar Activities: Changes in solar irradiance in wavelengths and other variations such as solar flares or sunspots, if larger enough, could have an unprecedented impact over global warming and atmospheric temperatures.

Global Warming: Its Effects and Impacts

The major impacts of global warming include societal, economic, and health impacts. It can cause a lot of harm if it continues the same way as it is happening now. Here are its certain impacts:

1. Rise in Temperature Leading to Ice Melt: Melting glaciers and snow melts will cause severe water shortages and droughts with higher frequencies giving way to heatwaves and extreme weather conditions in the mid-latitudes. Thinning ice of the northern seas will make the atmospheric conditions vulnerable to control.

2. Ecological Risks: Global warming has contributed to the extension of drier climatic zones such as deserts in the subtropics. Mostly ecosystems and animal life will be affected by higher carbon dioxide levels and global temperatures leading to climate change, which will result in the extinction of many species and reduced ecological diversity.

3. The Threat to Marine Life: Global warming can lead to the destruction of marine and coral life underwater. Higher content of carbon dioxide in the water inflicts damage to valuable natural resources.

4. Loss of Settlements: Global warming can also lead to Inundation from sea level rise, which can further threaten infrastructure and establishments of human settlements. This severely leads to a decrease in the human population. Droughts, temperature rise, loss of glacial rivers puts the state of agriculture on ain the rampage.

5. Health Factors: There are various indirect effects such as malnutrition inflicted by crop failures. Scanty rainfall leading to desertification can also cause several diseases due to global warming.

Flooding in low-altitude regions: Rise in sea level and high flooding tendencies can damage human habitation and cause mass destruction.

Potential Effects of Global Warming

Various assumptions about projected rates of population growth, economic expansion, energy demand, technology improvement, climate mitigation, and other aspects are used to create the scenarios. Simulations of future climate change include patterns of warning It is anticipated that the area of the North Atlantic Ocean south of Greenland will only be slightly warm. It is predicted that this anomaly would develop as warm northward ocean currents diminish and the jet stream shifts, bringing cooler polar air masses to the area, precipitation pattern is anticipated that changes in precipitation patterns would increase the likelihood of both drought and flood conditions in many regions, regional predictions include Increased winter precipitation in the arid southwest of the United States could make the drought worse in places like South Africa, ice melt and sea level rise, ocean circulation changes and tropical cyclones.

Environmental Consequences of Global Warming

Biological systems may change because of climate change and global warming. More precisely, variations in near-surface air temperatures are anticipated to have an impact on ecosystem processes and, consequently, the diversity of plants, animals, and other life forms. Plant and animal species have developed their current geographic ranges because of adaptation to long-term seasonal climate patterns. If global average surface temperatures climb by another 1.5 to 2.5 °C (2.7 to 4.5 °F) by the year 2100, a significant portion of plant and animal species are anticipated to be in increased danger of extinction. For warming above 4.5 °C (8.1 °F), a level that could be attained in the IPCC's higher emissions scenarios, species loss estimates increase to as much as 40%. The food webs within ecosystems would certainly undergo significant alterations because of a 40% extinction rate, which would be detrimental to ecosystem function.

Surface warming in temperate regions is likely to affect a variety of seasonal processes, including changes to the timing of egg laying and hatching, earlier leaf production by trees, earlier vegetation greening, and changes to the seasonal migration patterns of birds, fish, and other migratory animals. Polar bears and walruses, two species that depend on broken sea ice for their hunting activities, are threatened by changes in the seasonal patterns of sea ice in high-latitude habitats. The populations of algae and plankton are likely to decrease or be redistributed in the high latitudes due to a combination of warming temperatures, a drop in sea ice, changes in ocean salinity, and changes in ocean circulation. According to the study, if surface warming rose to preindustrial levels of roughly 4.3 °C (7.7 °F), 16% of Earth's species would disappear.

Socioeconomics Consequences of Global Warming

Depending on how much the global temperature rises during the coming century increases, the socioeconomic effects of global warming may be significant. According to models, regions (especially the tropics and high latitudes) would suffer economic losses and other regions would profit economically from net global warming of 1 to 3 °C (1.8 to 5.4 °F) above the late 20th-century global average.

Interesting Facts

• The world has had the maximum rise of CO₂ in 800,000 years.

• The year 2017 was the second hottest year followed by 2014.

• The US national park is only left with 26 glaciers out of 150.

Key Features

• Earth's climate has changed since the beginning of geologic time and that human activities have increasingly affected the pace and scope of current climate change

• The temperature of the Earth's surface and lower atmosphere can be explained by radioactive force.

• Greenhouse gas, water vapour, carbon dioxide, nitrous oxide and methane influence environmental change.