Emissions and Climate Change

Climate change is one of the greatest environmental challenges of our time, with the potential to alter all aspects of human life. A significant factor in climate change is the emissions that are released into the atmosphere by human activity. Here we look at the science behind climate change, its potential impacts, and how clean energy can help.

How the Earth's Climate is Regulated

The Earth's climate is largely dictated by the makeup of its atmosphere and the ways in which the atmosphere interacts with energy from the sun. The atmosphere is composed of multiple gases, primarily nitrogen (78%), oxygen (21%), argon (1%). These proportions vary with levels of water in the atmosphere, which can make up nearly 7% of the atmosphere's composition depending on weather patterns. The atmosphere also includes small but important amounts of the gases that create the earth's greenhouse effect, trapping the sun's heat within the atmosphere. These gases include carbon dioxide, methane, nitrous oxide, and ozone - the greenhouse gases.

The sun's energy is carried to the Earth in waves. When this energy reaches the atmosphere, several things happen. A certain amount of energy is reflected by the gases that make up the atmosphere. A larger portion passes through to reach the Earth's surface. When it hits the surface, it creates heat that is released back into the atmosphere. Some of this rising heat passes through the atmospheric barrier, and some is deflected back to Earth by the greenhouse gases.

The heat blocked by greenhouse gases and retained in the atmosphere helps determines the global climate and keeps Earth in the right temperature range for supporting life. If the amount of greenhouse gases increases, then the Earth's temperature increases.

The amount of greenhouse gases in the atmosphere is primarily determined by natural cycles of emissions and "sinks". For example, carbon dioxide in the atmosphere is absorbed by plants that break it down into carbon and oxygen and use the carbon as a nutrient. Animals that eat the plants absorb carbon into their bodies and release carbon dioxide into the air when they breathe. Finally, when plants and animals die and decompose, they release more carbon dioxide back into the air. A similar cycle occurs with the oceans, which both absorb and release carbon dioxide. Both plants and oceans are considered "sinks" in these scenarios because the carbon dioxide essentially sinks back into the earth through their absorption.

Human Activity and Climate Change

When more greenhouse gases are released than can be absorbed by natural cycles, they trap more heat from the sun within the atmosphere. This increases the average global temperature and affects climate patterns around the world.

Where do these additional emissions come from? Certain human activities are their primary sources, including electricity production, transportation, and industrial and residential activities. Most of these activities use power produced by the burning of fossil fuels, which releases emissions into the air. On the other side of the cycle, activities like deforestation that remove carbon-dioxide absorbing plants have reduced the Earth's ability to reabsorb greenhouse gases.

As a result of human activities, carbon dioxide concentrations in the atmosphere have increased by 25% over the past 200 years. Although carbon dioxide concentrations in the atmosphere vary naturally over time, this level of increased concentration over a short time period is unprecedented. In correlation to this increase, average global temperatures have also risen over the past 200 years. Although some of this increase may be attributed to natural variations, scientists believe that at least 60% is the result of increased greenhouse gas levels caused by human activity.

Impacts on People and the Environment

Scientists agree that the Earth's climate is getting warmer. The exact impact on people and the environment is less straightforward, but there is strong evidence for many negative impacts.

According to the Intergovernmental Panel on Climate Change, an authoritative international body that has brought together hundreds of leading scientists to analyze climate change, the rise in global temperature is expected to reach 3-4 degrees by the end of this century. This rise may seem small, but it can have dramatic, and devastating, impacts.

One of the most significant indicators of global warming is the melting of polar ice caps and glacial bodies, which releases enormous amounts of water into the oceans and rivers and contributed to rising sea levels. The melting of polar ice caps is already being documented and sea level rises have submerged two uninhabited islands in the Pacific, threatened several inhabited islands in the same area, and caused erosion in many coastal areas of the world. If temperatures continue to rise, many countries will be threatened by more significant sea level rises.

Changes in global climate also create changes in weather and local temperature patterns. More erratic weather events as well as more extreme seasonal temperature changes are predicted to occur if the global temperature continues to increase. Some areas are likely to be hit by more severe catastrophic weather while others may experience drought or increased rainfall, affecting water supplies and agriculture. Other predicted impacts include decreases in biodiversity and changes in the composition of forests due to local climate change.

All of these impacts on the environment will also impact people. Temperature extremes and catastrophic events are expected to result in increased death rates. Certain diseases now only found in tropical areas are expected to emerge in previously unimpacted areas. These impacts, as well as sea level rises and disrupted agriculture have the potential to hurt living standards and economies around the world.

How Clean Energy Can Help

Clean energy technologies can help mitigate climate change because they create few or no greenhouse gas emissions. Technologies like solar and wind rely on natural energy and do not require the burning of fuels like coal, natural gas, and oil. Biomass technologies do require fuel burning, but they release far fewer emissions than fossil fuels. Super-efficient technologies like fuel cells also help to reduce climate change emissions.