Three key facts about rising sea levels need to be pointed out to the world"s politicians and planners: sea-level rise is now unavoidable (不可避免的), it will happen faster than most of us thought, and it will
go on for a very long time.
Even if greenhouse gas emissions (排放) stopped tomorrow, the oceans would continue to become
larger as they get warm. The climate scientists estimate that sea-level rise may be in the range of 1 to 2
meters by 2100, with a small risk of an even greater rise.
For many islands and low-lying regions, even small rises will cause disasters. But for most countries,
the problem is what has been built on that land: New York, Sydney and Tokyo, to mention just a few
cities. Unless something can be done, great areas of urban network will disappear under the waves. It
will take a great engineering effort to protect these cities-an effort that may be beyond economies that
have been brought to their knees.
None of this means we should fear, and stop trying to forbid emissions. But together with these efforts,
we need to start acting now and we must stop building in danger zones.
Billions of dollars are being spent on constructing homes, offices and roads in vulnerable (脆弱的)
coastal areas. For instance, the skyscrapers of Shanghai are being built on land that is mere 4 meters
above sea level on average, and they are sinking under the weight of the buildings. Therefore, planning
for new coastal developments is to go against reality. If we want to build a lasting heritage for our children,
we should do so on the plentiful land that is in no danger from the sea. It is one of the effective ways to
slow down climate change, and we should be acting on it now.