A
（2021·广西梧州市·高三月考） Corals are often described as undersea forests, but they are declining far more quickly than the Amazon. The coral reefs( 珊 瑚 礁 )are likely to be among the first ecosystems to be wiped out by climate change.
A temperature rise of just 1 to 2℃ can lead to the death of the algae( 海 藻 ) upon which corals depend, draining them of color and making the structure more fragile. These bleaching( 褪 色 的 ) events can be temporary if waters cool, but the more frequent they are and the longer they last, the greater the risk of damage is.
But that’s exactly what is happening. Bleaching was first observed in 1983. It was seen on a global level in 1998, then 2010, and then from 2015 to 2017. Most available scientific evidence tells us that unless we do something to limit warming to 1.5℃, we will lose 99% of the world’s coral reefs in coming decades.
But there are other threats beyond warming. Off the Philippine island of Palawan, its old reefs have been badly damaged by dirty water from the tourist holiday center, pollution from boats and overfishing. The area ought to be a shelter because it’s one of the ocean regions most tolerant of climate change. “Even here, we are losing our corals,” said David Obura, chair of the Global Specialist Group in the International Union for the Conservation of Nature. “We need to reduce stress from overfishing, coastal development, pollution and tourism.”
“I am a generation of scientists watching them disappear. It is very depressing.” Obura said. “Above 1.5℃, in about 50 years, they will be a treasure of historic movies and pictures, but very little to see in real life. Children born today may be the last generation to see coral reefs in all their glory.”
1．The rising temperature affects corals by .
A．darkening their color
B．harming their structure
C．cutting their food sources
D．narrowing down their living area
2．What happened after 2015 according to the text?
A．Coral bleaching first became a global issue.
B．The ocean temperature went up steadily.
C．We lost 99% of the world’s coral reefs.
D．Worldwide coral bleaching lasted longer.
3．What factor that threatens corals is stressed in Paragraph 4?
A．Illegal fishing
B．Climate change
C．Ocean pollution
D．Global warming
4．What can be a suitable title for the text?
A．Experts worry about global warming.
B．Philippine coral reefs are under threat.
C．Record undersea forests before it is too late.
D．The next generation may never see coral reefs.
