By the article, what is the meaning to have“non-meat” days ...

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Climate change solutions

According to climate experts, one big problem we have right now is too much CO2 in the air. If we can out CO2 into the air, can we take it back out? At the moment, trees do this job - just not fast enough. So could we make treelike machines to do the job? Scientist Klaus Lackner of Columbia University in New York says yes and several companies are already developing the idea.

Smarter power for vehicles

• Electric car are more and more common all over the world, and the technology is getting better. And if you recharge the batteries with electricity which comes from solar and wind power, they are very clean technology.

• By law, the petrol sold in Brazil is 25% ethanol - a fuel made from sugar. It pollutes less than ordinary petrol. However, growing the sugar uses a lot of energy, and some people say the fuel can damage car engines.

• Hydrogen - a natural part of water - is used in some vehicles, including buses in cities around the world. It’s a great fuel, because the only waste it produces is water. The big problem is that making hydrogen fuel creates a lot of pollution.

Smoke to make shade?

Smoke from volcanoes and forest fires is known to block the sun and cool the Earth. Scientists at the University of Bristol in the UK have done experiments to test the idea of creating smoke to cool the world. The idea is disliked by most experts as a possibly very dangerous way to fight climate change. Dr Hugh Hunt, director of the research projects, said that the technology won’t be developed in the near future.

A vegetarian diet?

According to a report by the United Nations, producing meat creates more greenhouse gas emissions than transport - 18% of the world’s total. Eating less meat would help to reduce emissions and possibly fight global warming. Cities in Belgium, Brazil, Germany and South Africa - among many others - have “no-meat” days to bring the issue to people’s attention, and try to fight climate change close to home.

These are big ideas, but the solution in the end may be a big sum of small actions.

LANSFORD, L. Keynote Intermediate Workbook: 1. ed. National Geographic Learning, a part of Cengage Learning, 2016