Plants are flowering faster than scientists predicted in reaction to climate change, which could have long damaging effects on food chains and ecosystems.
Global warming is having a great effect on hundreds of plant and animal species around the world, changing some living patterns, scientists say.
Increased carbon dioxide (CO2) in the air from burning coal and oil can have an effect on how plants produce oxygen, while higher temperatures and changeable rainfall patterns can change their patterns of growth.
“Predicting species' reaction to climate change is a major challenge in ecology，” said the researches of several U．S. universities. They said plants had been the key object of study because their reaction to climate change could have an effect on food chains and ecosystem services.
The study, published on the Nature website, uses the findings from plant life cycle studies and experiments across four continents and 1,634 species. It found that some experiments had underestimated(低估) the speed of flowering by 8.5 times and leafing by 4 times.
“Across all species, the experiments underpredicted the speed of the advance—for both leafing and flowering—that results from temperature increases，” the study said.
The design of future experiments may need to be improved to better predict how plants will react to climate change, it said.
Plants are necessary for life on the Earth. They are the base of the food chain, using photosynthesis(光合作用)to produce sugar from carbon dioxide and water. They let out oxygen which is needed by nearly every organism on the planet.
Scientists believe the world's average temperature has risen by about 0.8℃ since 1900, and nearly 0.2℃ every ten years since 1979.
So far, efforts to cut emissions(排放) of planetwarming greenhouse gases are not seen as enough to prevent the Earth heating up beyond 2℃ this century—a point scientists say will bring the danger of a changeable climate in which weather extremes are common, leading to drought, floods, crop failures and rising sea levels.
语篇导读
本文为说明文，介绍了全球变暖的气候环境会让植物提前生长开花，进而影响整个食物链及生态系统。
1．What is the key information the author wants to give in Paragraph 1?
A．Plants' reaction to weather could have damaging effects on ecosystem.
B．The increasing speed of flowering is beyond scientists' expectation.
C．Climate change leads to the change of food production patterns.
D．Food chains have been seriously damaged because of weather.
解析 B 细节理解题。根据第一段可知，作者是要告知读者植物开花的增速超出了科学家的预期，故选B项。
2．What can we learn from the study published on the Nature website?
A．Plants' flowering is 8.5 times faster than leafing.
B．There are 1,634 plant species on the four continents.
C．Scientists should improve the design of their experiments.
D．The experiments failed to predict how plants react to climate change.
解析 C 推理判断题。根据第五段第二句可推出，对于植物所设计的实验应该有所改进，故选C项。
3．Why do scientists pay special attention to the study of plants?
A．Because they can prove the climate change clearly.
B．Because they are very important in the food chains.
C．Because they play a leading role in reducing global warming.
D．Because they are growing and flowering much faster than before.
解析 B 细节理解题。根据第四段第二句可知，植物对气候变化的反应对整个食物链和生态系统都至关重要，故选B项。
4．What can be inferred from the last two paragraphs about the world's temperature?
A．It has risen nearly 0.2℃ since 1979.
B．Its change will lead to weather extremes.
C．It is 0.8℃ higher in 1979 than that of 1990.
D．The rise of the temperature needs to be controlled within 2℃ in this century.
解析 D 推理判断题。根据最后一段可知，如果本世纪地球变暖超过2℃，便会出现极端天气，由此可推出，这个世纪地球温度的上升需要控制在2℃的范围之内，故选D项。
