Our carbon culture

In countries with cold winters, people burn fuel to keep warm. Some use open coal fires, but most houses now have central heating fueled by coal, oil, gas, or electricity. Gas is also widely used for cooking. Some electricity is generated without using fossil fuels, but all the other systems use them and release carbon dioxide, contributing to climate change. odern society runs on fossil fuels. We use them to power our cars, trucks, trains, ships, and aircraft. They run our industries, heat our...

Vulnerable cities

Sea levels will keep rising as more glacial meltwater pours into the oceans. By the year 2100, they are likely to be 8-24 in (20-60 cm) higher than they are now, provided that nothing catastrophic happens to the great continental ice sheets of Greenland or Antarctica. This may not seem too threatening, but many of the world's great cities are built on low-lying coasts, and are at risk from flooding. One of the most vulnerable is Shanghai in China a city of 18 million people built on land that...

Earths Climate

Our planet is a small oasis of life in the vastness of space. There may be others in the universe, but this is the only one we know about. Earth is close enough to the Sun to stop the oceans from freezing solid. A force of attraction called gravity holds on to the planet's atmosphere, and this provides living things with vital gases. It also acts like an insulating blanket, keeping temperatures within the limits that allow life to survive. Earth is a unique planet. It is the only one in the...

Greenhouse Gas Emissions By Weight

A number of gases released through human activity are increasing the power of the greenhouse effect. This diagram shows the relative quantities of the major human-produced greenhouse gases. The most important is carbon dioxide, because so much of it is released every year. The other greenhouse gases are emitted in smaller quantities, but they have a big effect because they are more powerful than carbon dioxide. extraction, processing, and distribution 8.4 Of all the greenhouse gases that we are...

The Greenhouse Effect

Water Vapor Greenhouse Gas

Earth would be a lifeless ball of rock if it did not have an atmosphere. This is partly because living things rely on the atmosphere to supply them with essential elements such as carbon, nitrogen, and oxygen. Living things also depend on the atmosphere to maintain the temperature that they need to survive. The layers of air that surround the planet act as both sunscreen and insulation, shielding life from the fiercest of the Sun's rays while retaining heat that would otherwise escape back into...

Burning the Forests

Climate change is being caused by a combination of factors, but the most important is the increase of greenhouse gases in the atmosphere, and especially carbon dioxide. Most of this extra carbon dioxide is being released by burning carbon-rich fuels. This is the same process that turns sugar into energy in our bodies, but it is more violent, releasing the energy as searing heat. The most basic of all fuels is wood, which people have been burning for thousands of years to keep warm and to cook...

What scares the scientists

If we do not make every effort to combat climate change, global temperatures could rise high enough to trigger events like the mass melting of Arctic permafrost, or huge wildfires in Amazonia. These would release more greenhouse gases, accelerating global warming. We know that such catastrophic climate change has happened in the distant past. To stop it from happening again, we must act now, before events move beyond our control. Vast areas of the far north are frozen below ground. In summer...

The Carbon Cycle

Carbon exists in pure form as graphite the leadin a pencil, for example and diamonds. Yet if it combines with oxygen, it forms carbon dioxide gas, and with hydrogen it forms methane. Green plants use carbon dioxide to make food. They absorb it from the air, and use the Sun's energy to combine it with water to make a carbohydrate, sugar. Sugar stores energy, and if it is combined with oxygen, the energy is released to fuel life processes. This reaction also turns the sugar back into water and...

Fossil Fuels

Fossil fuels are the remains of living things that were buried underground before they had time to decay. Coal is made of plants, so it contains the remains of the carbohydrates they created using the energy of sunlight. So coal is stored solar energy, compacted over millions of years. For thousands of years, timber was the main fuel used for heating, cooking, and in the form of charcoal industrial processes like metalworking. But in the 1700s, people started mining coal, which is a more...

Checks and Balances

The energy that Earth soaks up from the Sun is more or less balanced by the energy that it radiates out into space, but only in the long term. Short-term imbalances can make the planet colder or warmer. These temperature changes can lead to mass extinctions, like the one that wiped out the dinosaurs 65 million years ago. Once the balance is upset, this can lead to other changes in Earth's climate system, which are called feedbacks. There are two types of feedback. Negative feedbacks resist...

Warming oceans

As ocean water warms up, it expands like the liquid in a thermometer, so sea levels rise by a small amount. But gauges like this show a much greater actual rise, indicating that melting ice is adding to the problem. The effects of rising global temperatures are often dramatic on land, causing heatwaves, wildfires, and vanishing glaciers, but their impact on the oceans is less obvious. So far the oceans have not warmed as much as the continents. This is partly because they warm up more slowly....