On 5th June, countries around the Globe, joined hands and showed their determination to manage natural resources and deal with one of the most demanding challenge of the 21^st century- climate change. The theme for the World Environment Day 2009 was 'Your Planet Needs You - Unite to Combat Climate Change.' However, as the struggle continues, the immediate question that requires a quick answer is ‘What causes climate change?” 

Although the Earth’s climate evolves naturally over time, the major cause of climate change is the release of man made chemicals in the atmosphere. While these chemicals are necessary to produce certain items, operate essential refrigeration equipment, or make our daily lives easier, they are a danger to the environment and our health.   

Many systems that we rely upon on a day-to-day basis contain refrigerant gas, which is a major cause of climate change. The gas that is used to run commercial refrigeration units and air conditioning systems contains chlorofluorocarbons and hydro chlorofluorocarbons which contribute to global warming. These gases deplete the ozone layer. Because of the great harm refrigerant gas can cause to the Earth, the United States of America and many international countries are phasing out its usage, with complete removal by 2015. 

Organic chemicals such as endosulfan, chloripyrifos and phenol (commonly used as agricultural pesticides and industries) are dangerous to the environment. Exposure to sublethal concentrations of these chemicals can cause stress that limits an organism’s ability to survive or tolerate changes in environmental factors such as temperature. With the exception of phenol, prior exposure to sublethal concentrations of the chemicals affects the ability of fish to tolerate progressive temperature increases. Rising global temperatures and the presence of environmental contaminants may influence the survival of many organisms. As temperature influences the toxic effects of chemicals, so does chemical exposure influence the temperature tolerance of an organism. 

Fossil fuels are also a major cause of climate change because they lead to an increase in greenhouse gases in the atmosphere. Natural gas, oil and coal used in operating vehicles and generating electricity emit high levels of carbon dioxide, identified as a chief contributor to global warming. Fossil fuels also produce carbon monoxide, methane emissions, nitrous oxide and nitrogen oxides, all substances that impact air quality and global warming. 

Methane is also a significant cause of climate change. This greenhouse gas is discharged by cows, pigs, horses, sheep and other domesticated animals. It is also discharged from garbage in landfills, fertilizers, oil drilling and coal mining. In addition, when a gas leak occurs, a high volume of the dangerous chemical is discharged. 

Some daily household items and a number of common processes allegedly cause climate change. The use of aerosols, and animal agriculture, cement manufacturing, land usage and deforestation processes are all under study.

Common pollutants in our society include carbon dioxide, methane, nitrous oxide and black carbon and these pollutants are a cause of climate change. As they grow, the Earth's protective layer becomes damaged and this results in global warming. Scientists paint a doomsday scenario, where global warming will destroy the planet if no action is taken. 

Greenhouse gases in the air contribute to atmospheric heat, and this amount of heat stored in the atmosphere is a principal cause of climate change. Significant heat changes in the Earth's climate can affect all forms of life, including animal, plant, human and marine -all will be severely impacted. Simply put, too much atmospheric heat is the cause of climate change. The amount of greenhouse gases in the air contributes to atmospheric heat which creates significant changes in the Earth’s climate, affecting both land and ocean. As a result, human, animal, plant and marine life get severely impacted. 

The effects of global climate change on biodiversity and ecosystem functioning encompass multiple complex dynamic processes. Climate change and exposure to endocrine-disrupting chemicals (EDCs) are currently regarded as two of the most serious anthropogenic threats to biodiversity and ecosystems. Evidence shows that various organochlorine compounds, necessary such as polychlorinated biphenyls, dichlorophenyldichloroethylene, hexachlorobenzene, and oxychlordane, pose a threat to both human health and the environment. 

By Paul Twebaze Kashate

Anti-corruption Activist and advocate for Sustainable Natural Resource use.