Greenhouse Gases

Burning the Forests

Background Abstrak

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...

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....

Fossil Fuels

Isopar Viscosity

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...

Adding to the problem

Deforestation and the use of fossil fuels are not the only human activities causing climate change. Other aspects of modern life are adding to the problem. Some produce more carbon dioxide, as well as other greenhouse gases such as methane, nitrous oxide, and chlorofluorocarbons (CFCs). These other greenhouse gases are released in much smaller quantities than carbon dioxide, but they have a serious impact because they are much more powerful. A molecule of methane, for example, has the same...

Energy efficiency

Supplying power without using the fossil fuels that contribute to climate change is not easy. Wind farms, for example, produce far less electricity than fuel-burning power plants, and the wind does not blow all the time. But if we all used less energy, technologies such as wind and solar power would be able to cope with a bigger proportion of the demand. We can help to achieve this by improving energy efficiency, or making sure things use less power to do the same job. This applies both to the...

Green transportation

The transport of people and freight accounts for at least 14 percent of global greenhouse gas emissions. This figure is increasing, especially in many developing nations. Technology may help through the development of more efficient vehicles, powered by less polluting fuels. But most of the more exciting proposals are still at the design stage, and some may not work in practice. So in the short term, the best way to reduce greenhouse gas emissions from transportation is to change the way we...

Tidal barrages

Tidal Barage Outgoing And Incoming

A hydroelectric dam can be built across a tidal inlet on the coast. Gates in the dam open to allow water in as the tide rises every day. At high tide the gates are closed, and as the tide falls again, the water behind the barrage is allowed out through turbines linked to electricity generators. Some systems like this tidal plant in France exploit both the incoming and outgoing tide. Tidal barrages produce clean electricity, but they can be extremely damaging to coastal wildlife habitats because...

Power for the people

Big power plants generating megawatts of electricity are essential for keeping large-scale infrastructure running, but households and small communities can provide some or even all of their own power without using fossil fuels. Some is in the form of electricity, and some in the form of heat energy. A lot of the technology used to produce this local power is still being perfected it is not as efficient as it might be, and it can cost a lot. But its efficiency will improve, and as more people...

Heatwaves and droughts

By studying weather and climate data gathered from all over the world, and transmitted from orbiting satellites, scientists can compare it with past records to work out how much the world has warmed up. But for many people, the evidence of climate change is much more obvious. They are suffering heatwaves that can raise temperatures to lethal levels, and living with droughts that make drinking water scarce, kill their crops and farm animals, and turn fertile land to desert. Some of the droughts...

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...

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...

Public transportation

People who live in big cities routinely use buses, trains, and trams like these in the streets of Amsterdam in the Netherlands. These public transportation systems use energy much more efficiently than cars because they carry a lot of passengers, and often employ more efficient technology such as electric power. In rural areas, public transportation is less popular because the services are less frequent, so many people use cars. But rising fuel prices and road congestion could encourage more...

Nuclear power

There is one powerful, reliable energy source that, when it is up and running, emits no greenhouse gases at all. Nuclear fission exploits the colossal amount of energy released by radioactive uranium when its atoms are split in a nuclear reactor. But radiation is extremely dangerous, and since a reactor can also be used to make nuclear weapons, nuclear power is the subject of fierce debate between those who support this form of energy generation and those who oppose it. A single atom of uranium...

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...

Adapting to climate change

We have to combat climate change if we are to reduce the risk of catastrophic events in the future. Yet whatever we do, some change is inevitable. Even if we stopped all greenhouse gas emissions tomorrow, the average global temperature would still keep rising for the next 30 years, mainly because of the gradual release of heat stored by the oceans. The rising temperatures are bound to raise sea levels. They may also cause more droughts and floods, and create problems for agriculture and...

Geological evidence

Clues to the climates of the distant past can be found in the rocks. Some exposed rocks in the Sahara show scratches made by moving ice some 480 million years ago, and thick layers of red sandstone in northern Europe were once sand dunes that built up in scorchingly hot deserts. The thick white chalk rock at the top of this English cliff was formed in a shallow tropical sea during the age of the dinosaurs. Evidence from rocks, fossils, and other sources shows how Earth's average temperature has...

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...

The north pole

These images show the extent of Arctic summer ice in 1985, and its projected extent in 2085. Many scientists believe that by 2070, the thick pack ice that covers the Arctic Ocean at the North Pole could melt away entirely during the Arctic summer, leaving open water. This will be a catastrophe for the ice-breeding seals and polar bears that live in the region. The loss of summer ice and increased flow of fresh meltwater into the sea may also affect the currents that flow around the Arctic Ocean...

The Carbon Cycle

How Much Co2 Can Plant Absorb

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...

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...

Fossil Fuel Consumption

The main source of all the extra carbon dioxide in the atmosphere is the burning of fossil fuels. These include coal, oil in all its refined forms, and natural gas. All these fuels contain a lot of carbon. This chart shows that the annual consumption of fossil fuels varies by region and by country. The biggest consumers of fossil fuels are the United States, China, and the European Union. Coal produces far more carbon dioxide per unit of energy than the other fuels, so countries that burn a lot...

Think about what you eat

Beef Greenhouse Gases

A meat-rich diet adds to greenhouse gas emissions, because raising animals such as cattle adds a lot of methane to the atmosphere. Some of the meat that we buy is imported from far away, which uses fossil fuels and increases emissions. Some of it comes from places where rain forest has been cleared to provide grazing land for beef cattle. It has been calculated that every mouthful of beef that we eat represents the emission of 6,800 times its own weight in greenhouse gases. Central heating is...

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...

Disappearing wetlands

As droughts become more common and human populations grow and use more water, wetlands such as marshes and lakes are starting to dry up. These wetlands are vital to many animals, not only as places to live, but also as sources of drinking water, so their disappearance can be catastrophic for wildlife. Here scientists studying the effects of changing water levels in a Florida swamp wade up to their waists to gather samples. Many plants and animals are adapted for survival on high mountains where...

Combating climate change

Climate Change Flower

We must stop global temperatures from rising to the point where they cause dramatic, dangerous climate change. Since climate change is a global problem, it requires global action, but getting all the nations to agree on solutions is very difficult. This is partly because developed nations rely on the technologies that are causing the problem. They could have a lot to lose by replacing them, but they may have more to lose by risking climate chaos. New, less damaging technologies also provide...

Climate Change

Greenhouse Gases Climate

Satellite infrared image of Earth's temperature at night LONDON, NEW YORK, MELBOURNE, MUNICH, AND DELHI Project editor Margaret Hynes Managing editor Camilla Hallinan Managing art editor Owen Peyton Jones Art director Martin Wilson Publishing manager Sunita Gahir Category publisher Andrea Pinnington Picture researcher Sarah & Roland Smithies DK picture library Lucy Claxton, Rose Horridge, Myriam Megharbi, Emma Shepherd, Romaine Werblow Production editor Hitesh Patel Senior production...

Greenhouse gas producers

Climate change is being caused by humanity adding greenhouse gases to the atmosphere. These absorb heat radiated by Earth, and stop it from escaping out into space. There are several of these gases, and they come from various sources. Some nations release a lot more than others, partly because they are larger, but also because most of their citizens are richer and have a bigger carbon footprint. Most of the gases that are adding to the greenhouse effect are released by natural processes such as...

The next century

The global average temperature is certain to rise during the 21st century. Even if we were able to stop adding greenhouse gases to the atmosphere, the heat stored in the oceans would continue to be released over several decades. Exactly how this will affect the world is less certain, but there will probably be increasingly frequent and extreme heatwaves, droughts, and floods. More glaciers and polar ice will melt, and fragile natural environments will suffer, causing the extinction of many...

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...

Natural Climate Change

Climate scientists agree that the current rise in average global temperature is being caused by human activities. But climate change has occurred in the past, before people started changing the world, and indeed before humans existed. These shifts were caused by natural cycles that affect Earth's orbit around the Sun, by changes in solar radiation levels, and by catastrophic natural events such as massive volcanic eruptions. Some of these changes seem to have triggered positive feedbacks that...

Renewable energy

For centuries people have been harnessing the energy of wind and flowing water to power windmills and watermills. This technology has now been updated to drive electricity generators. Solar energy and even volcanic heat can also be turned into electricity. Such energy sources are described as renewable because they never run out. They may not be able to provide all our energy needs, but most of them do not release any of the greenhouse gases that are causing climate change.

Climate change and society

Climate change will have a big impact on human society, even if we manage to slow it down. The people who are likely to suffer most are those who have done least to create the problem those that live in the developing world. Many already have to cope with extreme climates, where farming and even getting enough drinking water can be difficult. Climate change and its effects will only make life harder, so there are likely to be more famines, mass migrations, and conflicts over land and resources....

The Human Impact

The last century has seen an average global air temperature rise of nearly 1.4 F (0.8 C), measured at ground level. This may not seem like much, but the world has warmed by only 7 F (4 C) in the 200 centuries since the peak of the last ice age, so this recent rise indicates a sharp upturn in the rate of warming. At the same time, we have enjoyed a technological revolution that has changed our lives, but this has been made possible only by massive consumption of energy. Most of this energy has...