Causes of Climate Change

Climate change is a phenomenon that we hear a lot about in the modern-day world, but what exactly is the definition of it. Britannica defines climate change as the periodic modification of Earth’s climate due to changes in the atmosphere and interactions between the atmosphere and other geologic, chemical, biological, and geographic factors within the Earth system, while NASA says that Climate change describes a change in the average conditions — such as temperature and rainfall. And yet National Geographic contends that climate change is the long-term alteration of temperature and typical weather patterns in a place. Climate change could refer to a particular location or the planet as a whole. But what evidence do we have to believe that this phenomenon is happening and what factors determine its severity?

 First of all, we need to differentiate between climate and weather, as many think that climate and weather are the same things. The definition of climate is the weather conditions that are expected in a region at a particular time of year; while, the definition of weather is the conditions outside right now in a specific place. Or to put it in other words, weather is immediate and easily changeable, and climate is determined and impacts a larger landmass. Now that we have a clear understanding of what we mean by saying “climate”, let’s consider the evidence of it’s occurring change. Researchers from NASA state this about climate change:

“ The Earth's climate has changed throughout history. Just in the last 650,000 years, there have been seven cycles of glacial advance and retreat, with the abrupt end of the last ice age about 11,700 years ago marking the beginning of the modern climate era — and human civilization.” This makes us assume that climate change has existed before we were able to study it. But recently the topic of climate change is amplified by the fact that the phenomenon is made severe, because of human activity. Thus we have more extreme consequences: the planet’s average surface temperature rose to 0.9 degrees Celsius since the late 19th century. This change is mainly caused by increased carbon dioxide. Because the oceans have absorbed most of this increased heat, their temperature also increased. Data from NASA's Gravity Recovery and Climate Experiment show Greenland lost an average of 286 billion tons of ice per year between 1993 and 2016, while Antarctica lost about 127 billion tons of ice per year during the same period. The rate of Antarctica ice mass loss has tripled in the last decade. Glaciers are retreating almost everywhere around the world, including the Alps, Himalayas, Andes, Alaska, and Africa. Satellite observations reveal that the amount of spring snow cover in the Northern Hemisphere has decreased over the past five decades and that the snow is melting earlier. So, because of this global sea level rose by about 20.32 cm in the last century. Since 1950, The number of high-temperature events has been increasing, while the number of record low temperatures has decreased. Since the beginning of the Industrial Revolution, the acidity of surface ocean waters has increased by about 30 percent. This happened because of an increased amount of carbon dioxide.

There are two types of causes of climate change: natural and human-caused. Natural causes include solar irradiance, tectonic and volcanic activity, orbital variations, and greenhouse gases. Solar irradiance played a big role in climate change in the past, as the sun is the main source of heat for the Earth, a more active sun caused higher temperatures, while the lesser - caused lower temperatures. volcanoes can influence the climate as they release carbon dioxide both in the atmosphere and the ocean. But the effect of all volcanic activity is a fraction of the effect of greenhouse gases. Greenhouse gases are gas molecules that have the property of absorbing infrared radiation emitted from Earth’s surface and reradiating it back to Earth’s surface, which causes a phenomenon known as the greenhouse effect. Carbon dioxide, methane, and water vapor are the most important greenhouse gases. Concentrations of greenhouse gases have varied during Earth’s history, and these variations have caused substantial climate changes. In general, greenhouse gas concentrations are high during warm periods and low during cold phases. Several processes influence greenhouse gas concentrations. Some of them are tectonic activities, vegetation, soil. Human activities—especially fossil-fuel combustion since the Industrial Revolution—are responsible for steady increases in atmospheric concentrations of various greenhouse gases, especially carbon dioxide, methane, ozone, and chlorofluorocarbons (CFCs). Orbital variation also plays a role in this occurrence as it affects: the shape of the earth’s orbit around the Sun, the tilt of the Earth’s axis concerning the sun, and the cyclic change to Earth’s orbital geometry, in particular: Earth’s axis of rotation wobbles, changing the direction of the axis concerning the Sun and the orientation of Earth’s orbital ellipse rotates slowly.

Above all human activities is the main reason the effects of climate change are so severe. In its Fifth Assessment Report, the Intergovernmental Panel on Climate Change, which is a group of 1,300 independent scientific experts from countries all over the world under the United Nations, concluded that there's a more than 95 percent probability that human activities over the past 50 years have warmed our planet. One of the activities that damage our planet is burning fossil fuels (like coal and oil). When they are burnt they release large amounts of carbon dioxide. Plants and trees play an important role in regulating the amount of carbon dioxide in the environment, so they play an important role in regulating the climate. But humans clear vast areas of trees and bushes around the world for farming, urban and infrastructure or to sell tree products such as timber and palm oil. When vegetation is removed or burnt, the stored carbon is released back into the atmosphere as CO2, contributing to global warming. Additionally, Animals, particularly livestock like sheep and cattle, produce methane, a greenhouse gas. When livestock are grazed at a large scale, the amount of methane produced is a big contributor to global warming. Also adding to this, some farmers use fertilizers that release nitrous oxide, which is another greenhouse gas.

From the following evidence, it is concluded that climate change is a periodical occurrence that has been repeated throughout thousands of years even without human interference, but it is made worse because of human activity and leads to severe consequences.

Bibliography

https://climate.nasa.gov/evidence/

https://climate.nasa.gov/causes/

https://climatekids.nasa.gov/climate-change-meaning/

https://climate.nasa.gov/resources/global-warming-vs-climate-change/

https://www.wwf.org.au/what-we-do/climate/causes-of-global-warming#gs.gvrrtc

https://www.nationalgeographic.org/encyclopedia/climate-change/

https://www.epa.gov/climate-indicators

https://royalsociety.org/topics-policy/projects/climate-change-evidence-causes/