Scientists have long understood the key role that oceans play in controlling the Earth’s climate. Oceans cover 70 per cent of the surface of the globe and store a thousand times more heat than the atmosphere does. What’s newer is the understanding of how this key component(组成部分) of our climate system responds to global warming.
A brake on global warming—for now
One of the oceans’ most important climate functions is absorbing heat and carbon dioxide(CO2), one of the gases that causes global warming. Acting as something absorbing heat, the oceans have absorbed huge amounts of heat and CO2 in the last forty years.
Fujita explains, “the oceans are saving us from faster climate change—they are putting a brake on the climate system.”
“That’s the good news,” he adds. “The bad news is that the oceans only slow the atmospheric warming. Once the oceans come to balance with a greenhouse-gas warmed earth, the extreme heat will remain in the atmosphere and things will get much hotter.” But where and how the oceans release this slowly increased heat is uncertain. And as the ocean stores heat, fragile(脆弱的) underwater ecosystems are struggling.
The most recent scientific report from the Intergovernmental Panel on Climate Change(IPCC) also notes with concern that the ocean is acidifying(酸化) because of increased absorption of atmospheric CO2. and thus causing a threat to shell-forming species. Sharp increase in CO2 levels will cause further acidification of the ocean.
Currents distributing heat
Another important role the oceans play is that of distributor(散布者). Oceans deliver heat and life-sustaining nutrition around the globe. Just as blood tube bring oxygen and nutrition to cells in the human body, the ocean’s currents carry oxygen, nutrients and heat throughout the Earth. The ocean distributes 25 to 50 per cent of energy the planet receives from the sun. For example, the Gulf Stream carries heat across the Atlantic. This warm current gives northwestern European a milder climate that it would normally have so far north. A change to the ocean’s circulation patterns could throw Europe into a colder period, even as the rest of the world is experiencing warmer temperatures.
小题1: We can infer from the passage that _______.
| A．the oceans cause global warming | B．the oceans stop global warming |
| C．the oceans release nutrients and heat | D．the ocean ecosystems face more dangers |
小题2: From the passage we can learn that ocean’s currents _______.
- produce oxygen and nutrients around
- absorb 25-50% of the energy from the sun
- distribute the atmosphere hotter
D. change the ocean’s circulation patterns
小题3: Which of the following are the results of the ocean absorbing heat and CO2?
a. It causes further acidification.
b. It makes the atmosphere hotter.
c. It balances the oceans with a green-house gas.
d. It affects shell-forming species.
e. It makes the oceans act as a heat sponge.
f. It controls the Earth’s climate.
| A．a-c-f | B．a-d-f | C．b-d-e | D．b-c-e |
小题4: If the ocean’s circulation pattern changed, ______.
| A．Asia would suffer a hotter climate. |
| B．Europe would become hotter |
| C．the rest of the world would become warmer. |
| D．the climate of Europe would become colder. |