OUR CHANGING PLANET
The Upsala Glacier in Argentina used to be one of the biggest glaciers in South America. In 1928, it was covered in ice and snow, but now the glacier is melting at an annual rate of about 200 m, so the area is covered in water. This is evidence of global warming.
Unit 2 Reading 1
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1In the last 100 years, the global temperature has gone up by around 0.75 °C. This may not sound like much, but such a small increase is causing sea levels to rise and threatening the habitat of many species of plants and animals. An increase of 2 °C in global temperatures could result in extinction for 30% of the world's land species.
2The Northwest Passage is a sea route which runs along the northern coast of Canada between the Atlantic and Pacific Oceans. In the past, it was often difficult to use because the water was frozen; however, increasing temperatures and the subsequent deglaciation¹ have made it easier for ships to travel through this route. The trouble is that the melting of the ice is leading to loss of habitat for the polar bears and other species which live in this area.
3Experts predict that global sea levels could rise by 30.5–122 cm by the end of the century. Consequently, some areas that were land a few hundred years ago are now under water, and many low-lying islands may be under water in the future.
4As a result of the changing climate, the world's ecosystems are also changing faster than ever before. More than one-third of the world's mangrove forests² and around 20% of the world's coral reefs³ have been destroyed in the last few decades. Forests are being cut down to provide land for food because human population is growing at such a rapid rate. Approximately a quarter of the land on Earth is now used for growing food. As a result of the higher temperatures and higher levels of carbon dioxide in the atmosphere, plants are producing more pollen, which could lead to more cases of asthma.
5What is causing climate change? The main cause is the huge amount of greenhouse gases, such as methane and carbon dioxide (CO₂), in the atmosphere, but the reason for this is the world's population – you and me. As the population increases, more land is needed to provide food and energy. Burning fossil fuels for heating, lighting, transport, electricity or manufacturing produces CO₂. Furthermore, humans breathe out CO₂, while trees "breathe in" CO₂ and produce oxygen, so by cutting down trees, we are increasing the amount of CO₂ in the atmosphere and reducing the amount of oxygen. As a result of human activities, CO₂ levels are now at their highest in 800,000 years.
6The biggest challenge we all face is to prevent further environmental disasters. We must do something before it is too late. We need to reduce the amount of CO₂ in the atmosphere. We need to stop burning fossil fuels and start using renewable energy. We can get enough energy from renewable fuels, such as solar energy, hydroelectric energy or wind power, to be able to stop using fossil fuels completely.