IELTS Upper

Read the text and answer the questions

The Changing Ocean

    Scientists have long stated that the main effect of global warming is the melting of the polar ice caps, resulting in a rise in sea levels. However, as we observed the theory become a reality, it is becoming apparent that this phenomenon also has multifarious secondary effects. 

    Fresh water from melting ice caps flows into the sea reducing the concentration of salt in the water and thus the sea's density. Saline-dense water would normally sink to the sea bed and then travel to warmer equatorial regions. Concurrently, the warmer, less densely saline water in warmer parts of the world would travel along the sea surface to the poles, where its salinity would increase and the water would consequently sink. However, as the salinity of polar water decreases, this ocean process slows down. This cycle is vital, however, as it has an oxygenating effect on the water and also carries nutrients from deeper water to the surface. Therefore, any slowing down of the cycle may have dramatic consequences for sea life. 

    A second alarming discovery is that the sea itself has traditionally played a role in reducing global warming. Oceans hold within them a certain amount of carbon dioxide. As the temperature of the sea rises, so its capacity to hold CO2 falls, thus the problem of global warming is further exacerbated. However, there is a piece of good news to counter this: melting ice caps and lower saline levels enable the sea to hold more carbon dioxide, so the problem could be offset to some extent.

Choose the correct answer

1) Dense water travels more slowly than warmer surface water.

• Not given
• True
• False

2) Nutrients are circulated less effectively as the salinity level of the sea in the polar regions decreases.

• Not given
• False
• True

3) More fresh water pouring into the sea accelerates the ocean cycle.

• Not given
• True
• False

4) Rising sea temperatures are mainly due to the sea being less able to hold carbon dioxide.

• False
• Not given
• True

5) Rising sea temperatures have resulted in the sea becoming less effective in curbing global warming.

• True
• False
• Not given