Climate change – the biology perspective

- Watch. -- Oh -- Nice -- It's a common chiff-chaff. A migratory bird. It has spent winter down south, and now it's back. But -- it arrives earlier nowadays than it used to. When I was a child the chiff-chaff returned almost two weeks later than today.

It's the climate that's changed. Many animals change their behaviour. -- Yes, the earth has become warmer. The average temperature of the earth has always varied, but in the last hundred years, the temperature on earth has increased at a faster rate than ever. This is global warming, and there is no doubt that human influence is the reason. Mainly due to the emission of greenhouse gases.

This has major consequences for people, animals and plants. Seamus notices that migratory birds change their habits when it gets warmer. And there are many other examples of species - both plants and animals - having their habitats changed. Around the North Pole, polar bears have become considerably skinnier during the last thirty years. When the ice melts, there is less space for the bears to live and hunt for food.

Some researchers fear that if the ice disappears, so will the polar bears. And at the South Pole, in Antarctica, the Adélie penguins have decreased in numbers during the same period of time. Thirty years ago, there were 32,000 mating couples. Today, only 11,000. Plants are also affected.

A warmer, drier climate has caused mountain pine beetles to proliferate. These insects have killed over 40 million hectares of pine trees in western North America. That's almost 70 million football pitches. And for everything that lives in the forests this means a radical change. That's how it works.

When climate change causes animals or plants to die or relocate, other animals experience increased competition for food, or perhaps themselves become prey for predators that were not there before. This affects the entire food chain, and can alter the whole ecosystem. Habitats are also changed for humans. If the polar ice-caps melt, the sea level rises, and large areas of land are submerged. In other areas, drought and bad harvests may occur where it used to be fertile.

What this means for the future we don't know for sure. The future is always hard to predict, but some scientists worry that many people will be forced to move, and that this will cause social unrest and conflicts. This sounds awful! What can we do? This is serious!

Some animals and plants are at risk of extinction, and whole areas might become uninhabitable for people, too. We need to stop global warming. It is not easy to know how, but we need political decisions that contribute to the decrease of greenhouse gases. And we need to stop deforestation and overfishing that alters the ecological balance. And we all need to consider what we do in our everyday lives.

Can we economize more... on petrol, electricity, or water? Everyone can think twice about their choices in everyday life. Everyone can contribute, in their way. For my part, I've put solar panels on the roof, so my electricity is a bit more climate friendly.