Climate Change | Global Issues Tours

Learn more about Climate Change
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What is climate change?
Who is involved?
Who is most affected?
Where are the consequences felt?
Why is it important?
Citations

What is climate change, anyway?

Climate change is the significant change of the Earth’s climate over time, including measures of temperature, rainfall, wind, humidity and atmospheric pressure. While there are natural variations in these measures, human activity has been linked to an increase in greenhouse gas emissions, which have over time led to a higher than average temperature on the planet.¹ 2010 was the warmest out of the last 131 years, as can be seen on climate maps.

Greenhouse gases include carbon dioxide, sulfur dioxide, methane, and CFCs. They build up in the troposphere and cause the warming of the Earth’s surface. When heat radiation rises towards the atmosphere, greenhouse gases absorb it and reradiate towards the surface, leading to increased warming.

Carbon dioxide (CO₂) is released into the atmosphere when fossil fuels are burned. CO₂ is a critical component of the Earth's atmosphere. Scientific studies indicate that CO₂ is one of several gases that trap heat near the surface of the Earth. These gases are known as greenhouse gases.² The rate of release of carbon dioxide emissions has tripled over the past 18 years, and the current concentration of CO₂ in the atmosphere is higher than in any time in the past 800,000 years.³

Methane (CH₄) is a colorless, odorless, flammable gas. It is formed when plants decay and where there is very little air. It is often called swamp gas because it is abundant around water and swamps. Bacteria that breakdown organic matter in wetlands and bacteria that are found in cows, sheep, goats, buffalo, termites, and camels produce methane naturally. Since 1750, methane has doubled, and could double again by 2050.⁴ Methane is 25 times more potent as a greenhouse gas than carbon dioxide, but there’s far less of it in the atmosphere.⁵

Who is involved in climate change?

The five countries that produce the highest carbon dioxide emissions are:

   1. China
   2. the United States
   3. Russia
   4. India
   5. Japan 6

Industrialized countries typically use a large share of fossil fuels to run their industries, technology, and transportation. When developing nations move their economies from agriculture to industry, they require more fossil fuels to keep up with the already industrialized nations.

Note how the United States stacks up in comparison to other countries’ carbon dioxide emissions. Emissions from the U.S. alone roughly equal to those of three nations put together—the U.K., Brazil, and China.⁷

Data from 2006 shows that China, the United States, and Russia are the top three overall emitters of carbon dioxide, with China and the U.S. at around 6 million metric tons a piece.

Who is most affected by climate change?

Climate change affects all nations and regions, but especially the poorest and most populated areas:⁸

In Africa, 75-250 million people will likely have no access to fresh water by 2020 and crops will be more difficult to grow because of drought. In delta areas with large populations there could be flooding.
In Latin America, shrinking glaciers will provide less drinking water and electricity; tropical rainforests will be transformed into savannahs; and food scarcity will become an issue as more and more land turns into desert and fewer fish live in the oceans.
In Southeast and East Asia, heavily populated areas will be at a higher risk of flooding. Coral reefs and mangroves will become increasingly extinct. Diseases like cholera will likely spread among the population, with high death rates.

Number of people affected by all natural disasters between 1976 and 2005.⁹ Climate change impacts the number of natural disasters, but is not the sole cause of them.

Where are the consequences of climate change felt?

To see the vital signs of the planet, check out this interactive map.

Small islands, coastal regions, large cities, and mountainous and polar regions are most affected by climate change. For example, glaciers in the Andes, Himalayas, and the Alps have been melting due to increased temperatures; melting has in turn made the sea level rise.¹⁰

Watch how climate change is impacting the Carteret Islands.

Why is climate change important?

Climate change will lead to dramatic changes in the overall environment, affecting humans, animals, and plants alike. For humans, disease and conflict are likely consequences of climate change. By putting clean air, safe drinking water, sufficient food, and secure shelter at risk, climate change threatens peoples’ health and safety.¹¹ Between 1991 and 2005, 76% of disasters around the globe were caused by weather extremes.¹² As the weather becomes more and more extreme, one would expect the number of natural disasters to increase.

Conflict
Conflict is another major consequence of climate change. Mass migrations will likely be necessary as people are forced to leave areas that are no longer livable due to climate or disaster. This will put pressure on less affected areas to take in new populations. In addition, people may begin to fight for control of increasingly scarce natural resources, like clean water.¹³
Effects on ecosystems
All three types of ecosystems—terrestrial, marine, and freshwater—will be affected by climate change, as will the plants and animals living within them. In terrestrial ecosystems, productive cropland and forest will be converted over time to deserts due to a decline in rainfall in many areas. Fire and insect outbreaks are predicted to be more common as well.¹⁴ In marine ecosystem, ocean acidification will be a major consequence of climate change. One third of all carbon dioxide emitted by humans is taken in by oceans,¹⁵ making the ocean water become acidic and corrode shells and reefs. Freshwater ecosystems will lose significant numbers of species because of climate change-related processes: rivers, streams, and wetlands could lose up to 49 species.¹⁶

See the Ecosystem Tour to get more detailed information about the three types of ecosystems.