What is global warming and climate change anyway?

By Clive Mutame Siachiyako

Global warming and climate change emerged recently in the vocabulary. The concepts evoke different things in people's minds. Some of the evocations have to do with scanty understanding of what the two concepts mean. I will use very basic language as much as I can with the hope of making others appreciate what it is and what they can do to save the earth from the effects arising from the two concepts.

Global warming refers to increasing temperature of the earth, which damages the ozone layer. The ozone layer is a membrane like ‘absorber’ of damaging ultraviolet sunlight (called UV-B) to nature. I can give an example of a human skin. When the skin opens up either due to an injury or otherwise, the inner part of the body becomes vulnerable to all sorts of infection, pickings, etc. Without its ‘skin’ to filter action on the ozone layer, the earth’s atmosphere becomes vulnerable to UV-B radiation destruction in the process affecting inhabitants that depend on it for survival. The ecosystem then fails to sustain human, animal, vegetation, etc., life.

Another example is what happens when we experience heat, fire, hot cooking oil or water burns. The skin loses its texture exposing the flesh. Without a bandage or something to protect the exposed flesh, most of us know what happens when something pricks us on that same spot. The pain and oozing blood...that happens to the atmospheric ‘being’ when exposed to sun radiation.

Climate change includes more to what is described above. It does not end at changes into temperature, but adds changes in wind, precipitation (rainfall patterns), season length, strength and frequency of extreme weather events such as droughts and floods. Climate change is more like an advanced stage of the ozone layer damage coupled with opportunistic ‘infections’ that disarray the earth’s ‘immune system.’ Thus, when we experience heat waves, melting polar ice, droughts, etc., we think of climate change, we talk about what is visible, the manifestations we can see.

The other difference between the two terms is related to scale. Global warming is a worldwide phenomenon. But climate change’s visibility is at global, regional or even more local scales. However, both global warming and climate change can produce different impacts depending on the local geography as well as the local inhabitants (plants, animals, nature, etc). Many of these changes cause unexpected and dangerous effects on life around the world.

Science of Climate Change

On a more technical level, I am using different ideas to present arguments surround the climate change science and effects of climate change on nature and its inhabitants. In examining the science behind climate change, I am also looking at the difference between climate and weather, and shed light about the greenhouse effect on the environment and how human behaviour contributes to the warming of our planet. REMEMBER, I promised no jargon, I will try being as plain as I can in putting varied issues across.

From the satellite data scientists looked at in studying weather patterns and measuring changes in crop yields and soil composition; our planet is, on average, is getting warmer. Temperatures have been rising since the late 1970s. The warming reflects long-term changes to the earth’s climate, and wherever you are, you could have seen certain changes in weather patterns...in African shortened rainfall span and frequent droughts, floods in Asia, melting ice and warmer seasons in Europe, etc.

Suffice to mention that when we talk about climate, we are not referring to weather. They mean two different things. Weather can change from season to season, day to day, even hour to hour. Sometimes when you least expect it. Weather reflects short-term conditions in the atmosphere. Meanwhile climate refers to the average temperatures and precipitation rates over an extended period of time. When these rates change over time, it can result in profound impacts on our planet. Impacts like rising sea levels, more extreme weather events, like droughts and floods, melting glaciers, shifts in ecosystems, as well as many others are real problems or manifests of global-climate change.

In the past, changes in climate resulted from natural causes, such as differences in the sun’s activity and volcanic eruptions. However, explaining the warming experienced in the past 100 years cannot be done without including greenhouse gases emitted by human activity.

What are these greenhouse gases?

These are several chemical compounds found in the atmosphere which would trap heat that would normally be released out to space. Some of these compounds occur in nature, such as carbon dioxide and methane. However, others are exclusively human-made and are found in sources like hair spray, paint fumes and aerosol sprays.

The greenhouse gases play a crucial role in warming the earth’s surface and making it habitable. However, too much human-generated greenhouse gas emissions upset the planet’s natural balance, leading to an increase in warming and end climate change.

How does climate change actually works?

Pollutants and other chemical compounds are released into the atmosphere due to human activity. The sun emits energy that is transmitted to the earth. About 30 percent of the sun’s energy is reflected directly back into space by the atmosphere, clouds, and the surface of the earth. However, greenhouse gasses in the atmosphere absorb much of the energy emitted from the warm earth’s surface, preventing it from immediately escaping from the earth’s system and back into space. As a result, too large a concentration of greenhouse gasses act like a blanket, making the earth warmer and throwing off the atmosphere’s natural energy balance.

Over the past 100 years, the amount of greenhouse gasses in our atmosphere has been increasing. This is largely due to carbon dioxide emissions from the burning of fossil fuels, such as coal, oil and gas. When these fuels are burned, carbon stored in them for millions of years is released in an instant — directly into the atmosphere — as carbon dioxide. 

Human activity currently releases over 30 billion tons of carbon dioxide into the atmosphere every year! The bad news is that greenhouse gas concentrations in the atmosphere will continue to increase, continuing to warm the earth — unless all nations reduce the billions of tons of greenhouse gas we produce each year. The good news is that the world is finally waking up to this global challenge, and there is much we can do to reduce our reliance on fossil fuels. During the 2015 Paris Climate Conference - COP21 countries made great commitments to reduce the emissions. Results are yet to be seen.

In the next act, I will explain on how climate change affects Africa and possibly other parts of the world.

References

Allison, Ian (2010). The science of climate change: questions and answers. Canberra: Australian Academy of Science, 2010.

Bernstein, Lenny, R. K. Pachauri, and Andy Reisinger (2008). Climate change 2007: synthesis report. Geneva, Switzerland: IPCC, 2008.

Melanie Nakagawa (2015). The Basics: The Science of Climate Change. Dec 8, 2015  yali.state.gov/courses

UNESCO/UNEP (2011). Climate Change Starter's Guidebook: An issues guide for education planners and practitioners. Paris: United Nations Educational, Scientific and Cultural Organization and the United Nations Environment Programme, 2011.