Passage Reference: Global warming is causing the Greenland ice cap to disintegrate far faster than anyone predicted. A study of the region's massive ice sheet warns that sea levels may - as a consequence - rise more dramatically than expected. Scientists have found that many of the huge glaciers of Greenland are moving at an accelerating rate - dumping twice as much ice into the sea as five years ago - indicating that the ice sheet is undergoing a potentially catastrophic breakup. The implications of the research are dramatic given Greenland holds enough ice to raise global sea levels by up to 21 feet, a disaster scenario that would result in the flooding of some of the world's major population centres, including all of Britain's city ports. Satellite measurements of the entire land mass of Greenland show that the speed at which the glaciers are moving to the sea has increased significantly over the past ten years with some glaciers moving three times faster than in the mid-1990s. B.

Tips: Look for strong warning language like catastrophic or disaster to spot the main idea.

Why the other options are wrong:

• As the ice sheet disintegrates sea levels will rise Faster.: This sounds close, but that heading fits better where the focus is on speed compared to predictions, not the disaster itself. This is a partial truth trap.

Key Vocabulary:

• disintegrate = break apart
• implications = possible results

Question Focus: Main idea - speed of sea level rise is faster than expected

Passage Reference: Scientists believe that computer models of how the Greenland ice sheet will react to global warming have seriously underestimated the threat posed by sea levels that could rise far more quickly than envisaged. The latest study, presented at the American Association for the Advancement of Science in St Louis, shows that rather than just melting relatively slowly, the ice sheet is showing all the signs of a mechanical breakup as glaciers slip ever faster into the ocean, aided by the lubricant' of melt water forming at their base. C.

Why this is correct: The paragraph explains that sea levels could rise much faster than expected because the ice sheet is breaking up, not slowly melting. Speed is the key idea here.

Tips: When a paragraph repeats ideas about speed or quicker change, choose a heading about pace or rate.

Why the other options are wrong:

• Software predictions have underestimated the effects OF crumbling glaciers.: Computer models are mentioned, but the paragraph's main focus is on how fast sea levels rise, not detailed criticism of software. This is an example-as-main-idea trap.

Key Vocabulary:

• envisaged = expected
• lubricant = substance that helps movement

Question Focus: Main idea - computer models fail to reflect real glacier behavior

Passage Reference: Eric Rignot, a scientist at the Jet Propulsion Laboratory and the California Institute of Technology in Pasadena, said that computer models used by the UN's International Panel on Climate Change have not adequately taken into account the amount of ice falling into the sea from glacial movements. Yet the satellite study shows that about two-thirds of the sea-level rise caused by the Greenland ice sheet is due to icebergs breaking off from fast-moving glaciers rather than simply the result of water running off from melting ice. 'In simple terms, the ice sheet is breaking up rather than melting. It's not a surprise in itself but it is a surprise to see the magnitude of the changes. These big glaciers seem to be accelerating, they seem to be going faster and faster to the sea,' Dr Rignot said. "This is not predicted by the current computer models. The fact is the glaciers of Greenland are evolving faster than we thought and the models have to be adjusted to catch up with these observations,' he said.

Why this is correct: This paragraph clearly criticizes computer models for not keeping up with real glacier changes. The repeated mention of models being wrong shows this is the main idea.

Tips: If experts are quoted criticizing methods or tools, the heading is usually about evaluation or error.

Why the other options are wrong:

• Sea levels may rise disastrously.: Sea level rise is mentioned, but only to support the argument about model failure. This is a context shift trap.

Key Vocabulary:

• magnitude = size or scale
• evolving = changing

Question Focus: Main idea - contrast between slow formation and fast reaction to warming

Passage Reference: the Greenland ice sheet will react to global warming have seriously underestimated the threat posed by sea levels that could rise far more quickly than envisaged. The latest study, presented at the American Association for the Advancement of Science in St Louis, shows that rather than just melting relatively slowly, the ice sheet is showing all the signs of a mechanical breakup as glaciers slip ever faster into the ocean, aided by the lubricant' of melt water forming at their base. C. Eric Rignot, a scientist at the Jet Propulsion Laboratory and the California Institute of Technology in Pasadena, said that computer models used by the UN's International Panel on Climate Change have not adequately taken into account the amount of ice falling into the sea from glacial movements. Yet the satellite study shows that about two-thirds of the sea-level rise caused by the Greenland ice sheet is due to icebergs breaking off from fast-moving glaciers rather than simply the result of water running off from melting ice. 'In simple terms, the ice sheet is breaking up rather than melting. It's not a surprise in itself but it is a surprise to see the magnitude of the changes. These big glaciers seem to be accelerating, they seem to be going faster and faster to the sea,' Dr Rignot said. "This is not predicted by the current computer models. The fact is the glaciers of Greenland are evolving faster than we thought and the models have to be adjusted to catch up with these observations,' he said. D. The Greenland ice sheet covers an area of 1.7 million sq km - about the size of Mexico - and, in places, is up to 3km thick. It formed over thousands of years by the gradual accumulation of ice and snow but now its disintegration could occur in decades or centuries. Over the past 20 years, the air temperature of Greenland has risen by 3*C and computer models suggested it would take at least 1,000 years for the ice sheet to melt completely. But the latest study suggests that glaciers moving at an accelerating rate could bring about a much faster change. The behaviour of the glaciers that dump ice into the sea is the most important aspect of understanding how an ice sheet will evolve in a changing climate,' Dr Rignot said. It takes a long time to build and melt an ice sheet but glaciers can react quickly to temperature changes. Climate warming can work in different ways but, generally speaking, if you warm up the ice sheet, the glacier will flow faster,' he said.

Why this is correct: The paragraph contrasts slow formation with fast response to warming. This contrast runs through the whole paragraph and defines its main idea.

Tips: When a paragraph compares past and present speed, look for contrast-based headings.

Why the other options are wrong:

• Sea levels may rise disastrously.: That idea belongs to earlier paragraphs. Here the focus is on how glaciers behave, not consequences. This is a wrong section trap.

Key Vocabulary:

• accumulation = gradual build-up
• evolve = develop over time

Question Focus: Main idea - explanation of factors affecting Greenland's ice balance

Passage Reference: The ice 'balance sheet' of Greenland is complex but - in simple terms - it depends on the amount of snow that falls, the amount of ice that melts as run-off and the amount of ice that falls directly into the sea in the form of icebergs 'calving' from moving glaciers.Satellites show that the glaciers in the south of Greenland are now moving much faster than they were ten years ago. Scientists estimate that, in 1996, glaciers deposited about 50 cubic km of ice into the sea. In 2005 it had risen to 150 cubic km of ice. Details of the latest study, published in the journal Science, show that Greenland now accounts for an increase in global sea levels of about 0.5 millimetres per year - compared to a total sea level rise of 3mm per year. When previous studies of the ice balance are taken into account, the researchers calculated that the overall amount of ice dumped into the sea increased from 90 cubic km in 1996 to 224 cubic km in 2005. F.

Why this is correct: The paragraph clearly lists three factors that control ice loss, then supports them with data. That structure matches the heading exactly.

Tips: If a paragraph says depends on or consists of, expect a heading about factors or causes.

Why the other options are wrong:

• As the ice sheet disintegrates sea levels will rise Faster.: Sea levels are mentioned, but only as a result of the three-factor explanation. This is a partial truth trap.

Key Vocabulary:

• run-off = melted water flowing away
• calving = ice breaking off

Question Focus: Main idea - changing glacier behavior spreading north

Passage Reference: Dr Rignot said. "This is not predicted by the current computer models. The fact is the glaciers of Greenland are evolving faster than we thought and the models have to be adjusted to catch up with these observations,' he said. D. The Greenland ice sheet covers an area of 1.7 million sq km - about the size of Mexico - and, in places, is up to 3km thick. It formed over thousands of years by the gradual accumulation of ice and snow but now its disintegration could occur in decades or centuries. Over the past 20 years, the air temperature of Greenland has risen by 3*C and computer models suggested it would take at least 1,000 years for the ice sheet to melt completely. But the latest study suggests that glaciers moving at an accelerating rate could bring about a much faster change. The behaviour of the glaciers that dump ice into the sea is the most important aspect of understanding how an ice sheet will evolve in a changing climate,' Dr Rignot said. It takes a long time to build and melt an ice sheet but glaciers can react quickly to temperature changes. Climate warming can work in different ways but, generally speaking, if you warm up the ice sheet, the glacier will flow faster,' he said. E. The ice 'balance sheet' of Greenland is complex but - in simple terms - it depends on the amount of snow that falls, the amount of ice that melts as run-off and the amount of ice that falls directly into the sea in the form of icebergs 'calving' from moving glaciers.Satellites show that the glaciers in the south of Greenland are now moving much faster than they were ten years ago. Scientists estimate that, in 1996, glaciers deposited about 50 cubic km of ice into the sea. In 2005 it had risen to 150 cubic km of ice. Details of the latest study, published in the journal Science, show that Greenland now accounts for an increase in global sea levels of about 0.5 millimetres per year - compared to a total sea level rise of 3mm per year. When previous studies of the ice balance are taken into account, the researchers calculated that the overall amount of ice dumped into the sea increased from 90 cubic km in 1996 to 224 cubic km in 2005. F. Dr Rignot said that there are now signs that the more northerly glaciers of Greenland are beginning to adopt the pattern of movements seen by those in the south. The southern half of Greenland is reacting to what we think is climate warming. The northern half is waiting, but I don't think it's going to take long,

Why this is correct: Among the remaining headings, this is the closest available match, even though it is not perfect. The paragraph talks about changes spreading north, not actual new glaciers.

Tips: When none are perfect, choose the heading that fits better than the others.

Why the other options are wrong:

• Global sea levels are Falling.: The passage never says sea levels are falling. This directly contradicts the whole text. This is a contradiction trap.

Key Vocabulary:

• northerly = in the north
• adopt = start using

General Tips:

• Read all headings first and underline key words like rise, models, factors.
• Focus on the paragraph's main idea, not just one sentence or number.
• Headings follow paragraph order, so move down the list step by step.
• If two headings seem similar, choose the one that covers more of the paragraph.