 We explain global warming and what you can do about it. Tom is shocked. The media is reporting the consequences of the hurricane on the Philippines. More than 5,000 people have died. Entire cities are flooded and devastated. But that's not all. The next report is about a famine in the Sahel. Because of a drought that lasted for months, the harvest has been exhausted and food is scarce. Is it possible that catastrophes like that are on the increase? Tom asks his friend Mary for advice. She explains that these extreme weather phenomena are getting worse due to changes in climate. But where does this warming come from? The greenhouse effect is the bad guy. The atmosphere protects the earth and stores the heat of the sun. As in a greenhouse, this is especially caused by the greenhouse gases, steam, carbon dioxide, and methane. This effect is actually essential to life. Without it, the temperature on earth would be well below freezing. Industrialization increased this effect to a dangerous level. So the real bad guy is man, and the warming is getting worse and worse. When polar ice and glaciers melt, they reflect less sunlight and the sea level rises. Millions of coastal inhabitants are in danger. Additionally, water evaporates, which increases the greenhouse effect. Also, grounds, which stored centuries-old methane, are thawing. The poisonous gas escapes and worsens the greenhouse effect. The vicious cycle starts again. That's how the average temperature on earth rose in the last century to around 0.74 degrees Celsius, which does not sound like a lot but has devastating consequences. Because the whole weather system changes, millions of people and countless animal and plant species are in danger of extinction. To stop this, scientist worldwide agree the emission of greenhouse gases has to be reduced. It starts with everyone individually, even Tom. But what exactly can he do? Thanks to Mary, Tom chooses energy-saving electronic devices and unclugs them after use. Also, he's improved the thermal insulation of his house to heat it more efficiently. And as often as he can, he takes the bus or bike instead of the car. Tom's taking care of the environment. Now it's your turn.