Global Warming

Climate Change - The Basics

The term, climate change is used to describe a long-term change in global temperatures and weather patterns.

The earth's temperature has changed drastically in its 4.5 billion year history, from the Huronian Ice Age that covered vast portions of the planet in ice for nearly 300 million years, to a period about 50 million years ago, when scientists believe that palm trees and crocodiles were native above the Arctic Circle.

Today, climate change is commonly used as a term to describe the effects of global warming that have occurred as a result of human activity following the industrial revolution in the 18th century.

Earth's atmosphere is full of gases. Some gases, including nitrogen and oxygen -- that together accounts for 99% of the gas in the atmosphere do not absorb heat from the sun, allowing it to reflect back into space from the Earth's surface.

Other gases, known as greenhouse gases -- including carbon dioxide, methane and nitrous oxide -- absorb heat and make up roughly 0.1% of the atmosphere. When these gases absorb solar energy, they radiate it back towards the planet's surface and to other gas molecules, creating the greenhouse effect.

The greenhouse effect plays an important role in naturally regulating the temperature of our climate. Without it the Earth's average temperature would -18C. That's roughly the temperature of a domestic freezer.

Since the industrial revolution the concentration of greenhouse gases in the atmosphere has been increasing as a result of human activities like burning fossil fuels, deforestation and modern farming practices. Which means more greenhouse effect, and more heating.

A 2013 report by the International Panel on Climate Change (IPCC), a UN body of climate scientists, found that the atmospheric carbon dioxide concentration had risen by 40% since the industrial revolution, resulting in earth's temperature increasing by 1C.

In 2018, the IPCC released a stark report on the effects of a 1.5C temperature increase. These include more extreme weather conditions, sea-level rising, the destruction of coastal ecosystems, loss of vital species and crops, population displacement and a huge cost to the global economy.

In 2018, the United Nations warned that without urgent action global temperatures are set to rise above 3C above pre-industrial levels by the end of the century.

At that temperature the outlook begins to look even worse -- Entire cities could be swallowed by the rising oceans, species of plants and animals face extinction as their ecological systems fail to adapt to the heat, and hundreds of millions of people could be forced to migrate due to coastal flooding, longer-lasting draughts and depleting crop yields.