What is Climate Change?

The Earth’s climate is constantly changing. In the past this has happened due to natural causes. In 2007, however, the global scientific community acknowledged the reality of human-influenced climate change.

Imagine that the atmosphere is a duvet surrounding the earth and each molecule of carbon dioxide (CO₂) is a feather inside. Every time we use energy we add more and more feathers to the duvet and this in turn keeps more heat in. If we continue like this, the global climate could become very uncomfortable for all earth systems; the same as sleeping with many duvets in the middle of summer!

The natural balance of atmospheric gases began to change with the industrial revolution, but over the past 50 years, with growing demands for higher global standards of living, increases in greenhouse gas concentrations in the air have accelerated creating the ‘Greenhouse Effect’.

What is the Greenhouse Effect?

There are six main greenhouse gases that help to form a protective blanket over the earth. These gases allow ultraviolet light (short- wave radiation) from the sun into the atmosphere. Upon coming into contact with the earth, this short-wave radiation is converted into infrared (long-wave) radiation, commonly known as heat, and is mostly absorbed, warming the earth.

The greenhouse gases stop the heat from escaping into space, keeping the earth warm. Without this, the earth would have an average temperature of -20°C… far too cold for most of us! So the atmosphere, with greenhouse gases, act like a natural greenhouse for the whole planet.

However, the more greenhouse gases we release into the atmosphere the more heat they trap and emit back into the inner atmosphere thus leading to ‘global warming’.

The risk is that human-induced global warming will lead to climate change with unknown, and possibly disastrous, consequences.

Greenhouse Effect © Katana.re

So, which are the Greenhouse Gases?

The main culprits are carbon dioxide (CO₂) and methane (CH₄).

A finite amount of carbon is stored on the planet in the atmosphere, the sea, living matter and fossil fuels.

The natural carbon cycle transfers between these stores roughly balance each other, for example, plants absorb carbon as they grow, but release it as they decay. But when we cut down trees or extract and burn fossil fuels, we release extra CO₂ into the atmosphere.

Human activities such as coal mining, landfills, agriculture (from the guts of cattle) and oil&gas extraction account for 60% of global CH₄ emissions. Although actual volumes are low, CH₄ is 21 times more potent as a greenhouse gas than CO₂.

So the more we consume (energy, water, food and other resources) and the more we produce (and waste), the more we contribute to climate change through our carbon emissions.

The Carbon Cycle Source: UNEP/GRID-Arendal

What are Carbon Emissions?

In order to stop global warming and climate change we first need to be able to identify and measure what we are producing. In 1997, the Kyoto Protocol officially identified the six greenhouse gases and created a global standard of measurement for emissions. As CO₂ is the most significant of the gases, everything is measured against the equivalent of one ton of CO₂ (tCO₂e) and referred to as ‘carbon emissions’.

Here are the six main greenhouse gases and how they compare to each other in terms of their Global Warming Potential (GWP)*:

1 ton Carbon Dioxide (CO₂) = 1 tCO₂e
1 ton Methane (CH₄) = 21 tCO₂e
1 ton Nitrous Oxide (N₂O) = 310 tCO₂e
1 ton Perfluorocarbons (PFCs) = 9,200 tCO₂e
1 ton Hydrofluorocarbons (HFCs) = 11,700 tCO₂e
1 ton Sulphur Hexafluoride (SF₆) = 23,900 tCO₂e
 

* GWP values for a 100 year time horizon have been used. There are many types of PFCs and HFCs, for purposes of illustration, the most impactful values are represented. (source: IPCC)

The total amount of carbon emissions we each emit is known as our ‘carbon footprint’.

Greenhouse Gases © Katana.re