Climate change is the term used to describe changes to the Earth’s climate due to global warming.
So, how exactly does global warming happen?
SUB-UNIT 1
Greenhouse Effect & Climate Change
We have heard a lot about climate change lately. But what exactly is climate change?
Climate change refers to long-term shifts in temperatures and weather patterns. These shifts may be natural, such as through variations in the solar cycle or changes in ocean currents. In fact, the Earth’s climate is constantly changing and has been for millennia.
However, in recent decades scientists have noticed that the climate is changing faster than ever before. This is due to a rapid increase in average global temperatures.
So you may be wondering, “Why is this happening? Why is the Earth getting warmer?”
To understand why you first need to learn about greenhouse gases.
Our Earth is surrounded by an atmosphere that contains a layer of gases, mainly nitrogen and oxygen, with trace amounts of argon and a certain class of gases known as “greenhouse gases”.
Greenhouse gases (GHG) include carbon dioxide (CO2), methane (CH4), nitrous oxide (N2O), ozone (O3) and water vapour. They are called greenhouse gases because they trap heat from the Sun, acting as a blanket that keeps our Earth at just the right temperature for life as we know it.
This is what we call the greenhouse effect. Greenhouse gases occur naturally in the atmosphere, without them, the Earth’s temperature would be around -18°C.
With the proper amount of greenhouse gases, the Earth stays at the ideal temperature. However, human activity since the Industrial Revolution has caused an increasing amount of GHG to be emitted into the atmosphere, causing average global temperatures to rise.
This increase in the Earth's temperature, known as global warming, adversely affects the Earth's climate. The changes to the Earth’s climate due to the rise in temperature are referred to as climate change.
The current problem is that greenhouse gasses in the atmosphere continue to increase.
How does this happen?
SUB-UNIT 2
Sources of Greenhouse Gases
According to climate scientists, the amount of greenhouse gases in the atmosphere continues to increase because of human activities.
Here are some of the major human-led drivers of GHG emission!
Burning fossil fuels is the primary source of the additional carbon dioxide (CO2) in the atmosphere. Fossil fuels are used primarily for electricity production and transportation.
Deforestation is the second-largest source of greenhouse gas emissions. Cutting and clearing of trees and forests for the facility of human activities such as agriculture & urban development are also contributing to release more carbon dioxide (CO2) into the atmosphere.
In addition to being a major driver of deforestation, agricultural activities also play a major role in GHG emissions. Livestock, especially cattle emitting methane (CH4) whereas plant cultivation is adding more nitrous oxide (N2O) from the use of non-organic fertilizers
Poor waste management is also a major source of GHG. Landfills that hold household waste emit methane (CH4) into the atmosphere.
Factories produce waste and pollution that contain carbon dioxide (CO2), methane (CH4) and nitrous oxide (N2O), adding more greenhouse gases in the atmosphere.
These activities cause the temperature of the Earth to rise as greenhouse gas concentration is increasing, causing climate change.
But how does climate change affect us?
SUB-UNIT 3
How is Climate Change Affecting Us
Whether or not you realize it, we are already experiencing the impacts from climate change. Now, let's take a deeper look at how climate change affects us all.
Since it was initially formed around 4.5 billion years ago, our Earth has undergone many major geological and biological changes. Climate change itself has occurred naturally over millennia. However, due to human activity in the last 250 years, the Earth’s temperature has risen faster than ever before.
The global warming that we are experiencing now is causing ice in the Arctic and Antarctic as well as glaciers and snow around the world to melt. This contributes to sea level rise that puts small islands in danger of sinking and disappearing in the future.
Also, the rising sea levels are causing devastating floods and represent an existential threat to low-lying island and coastal communities around the globe.
Another effect of global warming is the oceans becoming warmer and evaporating faster than normal, adding more moisture into the atmosphere, and contributing to more severe storms and heavy rainfall. This makes weather become more extreme, bringing longer droughts and heatwaves which increase the risk of wildfires. Because of this, many animals are forced to migrate to other areas to survive as they are losing their habitat.
Additionally, higher ocean temperatures lead to acidification. Ocean acidification is mainly caused by the decrease of pH levels of the ocean due to the absorption of CO2 in the atmosphere by the ocean, causing coral bleaching that affects marine ecosystems.
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These events are a picture of how the climate crisis looks like. This threatens human life with various impacts including food crisis, water shortage, new disease outbreaks, economic losses, and prolonged conflicts.
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