Science confirmed that human activity has increased the amount of greenhouse gases in the atmosphere. For example, burning fossil fuels for transport, deforestation, burning coal, oil or gas for electricity generation, unmanaged landfills, ruminant livestock, agricultural activities like using excessive use of industrial fertilizers, etc. This increase of greenhouse gases has led to the global temperature increase, which in turn causes  climate change.

Causes of rising emissions

• Burning coal, oil, and gas produce carbon dioxide and nitrous oxide.
• Cutting down forests (deforestation), trees help to regulate the climate by absorbing CO₂ from the atmosphere. When they are cut down, that beneficial effect is lost and the carbon stored in the trees is released into the atmosphere, adding to the greenhouse effect.
• Increasing livestock farming, because ruminant animals produce large amounts of methane when they digest their food.
• The use of excessive industrial-based fertilizers containing nitrogen produce nitrous oxide emissions.
• Fluorinated gases are emitted from equipment (refrigerator, air conditioners, etc) and products that use these F-gases. Such emissions have a very strong warming effect, up to 23 000 times greater than carbon dioxide.

How has human activity led to global warming?

Development activities have been on the rise since the beginning of the industrial revolution in the 1870s. Industries have used a variety of fuels, including coal, gas, and petroleum products, all of which emit greenhouse gas. This has been going on for a long time before people woke up to the fact that it would affect them. In addition, due to urban sprawl, construction, cooking, etc, forests have been cut down, and yet they are the potential removal of carbon dioxide (CO2) from the atmosphere. When forests are destroyed, carbon dioxide is emitted into the atmosphere, and this led to a high concentration of carbon dioxide emissions.

How do we know humans are responsible for global warming?

Scientists have studied past climate changes to understand the factors that can cause the planet to warm or cool. The big ones are changes in solar energy, ocean circulation, volcanic activity, and the amount of greenhouse gases in the atmosphere and they have each played a role at times.

In trying to determine the cause of current climate changes, scientists have looked at all of these factors. The first three have varied a bit over the last few centuries and they have quite likely had modest effects on climate, particularly before 1950. However, they cannot account for the planet’s rapidly rising temperature, especially in the second half of the 20th century, when solar output actually declined and volcanic eruptions exerted a cooling effect.

That warming is best explained by rising greenhouse gas concentrations. Greenhouse gases have a powerful effect on climate. Moreover, since the Industrial Revolution, humans have been adding more of them to the atmosphere, primarily by extracting and burning fossil fuels like coal, oil, and gas, which release carbon dioxide.

These rapid increases in greenhouse gases have caused the climate to warm abruptly. In fact, climate models suggest that greenhouse warming can explain virtually all of the temperature change since 1950. This has been confirmed by the International Panel on Climate Change (IPCC) on its first Assessment report.