• condense (condenses, condensing, condensed)
VERB When a gas or vapour condenses, or is condensed, it changes into a liquid.
■ [+ to-inf] Water vapour condenses to form clouds.
■ [+ into] The compressed gas is cooled and condenses into a liquid.
■ [+ out of] As the air rises it becomes colder and moisture condenses out of it.
• contract (contracts, contracting, contracted)
VERB When something contracts or when something contracts it, it becomes smaller or shorter.
■ Blood is only expelled from the heart when it contracts.
■ New research shows that an excess of meat and salt can contract muscles.
• expand (expands, expanding, expanded)
VERB If something expands or is expanded, it becomes larger.
■ Engineers noticed that the pipes were not expanding as expected.
■ The money supply expanded by 14.6 percent in the year to September.
■ [V-ing] a rapidly expanding universe
• flow (flows, flowing, flowed)
VERB If a liquid, gas, or electrical current flows somewhere, it moves there steadily and continuously.
■ [+ into] A stream flowed into the valley.
■ [+ into] The current flows into electric motors that drive the wheels.
Verbs associated with scientific study:
• estimate (estimates, estimating, estimated) (also overestimate, underestimate)
VERB If you estimate a quantity or value, you make an approximate judgment or calculation of it.
■ [+ that] The Academy of Sciences currently estimates that there are approximately one million plant varieties in the world.
■ He estimated the speed of the winds from the degree of damage.
• predict (predicts, predicting, predicted)
VERB If you predict an event, you say that it w ill happen.
■ Chinese seismologists have predicted earthquakes this year in Western China.
■ [+ that] Some analysts were predicting that online sales during the holiday season could top $10 billion.
■ [+ when] tests that accurately predict when you are most fertile
• state (states, stating, stated)
VERB If you state something, you say or write it in a formal or definite way.
table clearly states the amount of fat found in commonly used foods.
■ [+ that] The police report stated that he was arrested for allegedly assaulting his wife.
■ Buyers who do not apply within the stated period can lose their deposits.
• accurate (opposite inaccurate)
ADJECTIVE Accurate information, measurements, and statistics are correct to a very detailed level. An accurate instrument is able to give you information of this kind.
■ Accurate diagnosis is needed to guide appropriate treatment strategies.
■ a quick and accurate way of monitoring the amount of carbon dioxide in the air
• likely (opposite unlikely)
ADJECTIVE You use likely to indicate that something is probably the case or will probably happen in a particular situation.
■ Experts say a yes’ vote is still the likely outcome.
■ [+ that] If this is your first baby, it’s far more likely that you’ll get to the hospital too early.
Nouns associated with climate:
• current (currents)
1 NOUN A current is a steady and continuous flowing movement of some of the water in a river, lake, or sea.
■ [+ of] The ocean currents of the tropical Pacific travel from east to west.
■ The couple were swept away by the strong current.
2 NOUN A current is a steady flowing movement of air.
■ [+ of] a current of cool air
■ The spores are very light and can be wafted by the slightest air current.
• drought (droughts)
NOUN A drought is a long period of time during which no rain falls.
■ Drought and famines have killed up to two million people here.
• flood (floods)
NOUN If there is a flood, a large amount of water covers an area which is usually dry, for example when a river flows over its banks or a pipe bursts.
■ More than 70 people were killed in the floods, caused when a dam burst.
■ Floods hit Bihar state, killing 250 people.
• glacier (glaciers)
NOUN A glacier is an extremely large mass of ice which moves very slowly, often down a mountain valley.
■ University of Alaska scientists report that the state’s glaciers are melting faster than expected.
■ Twenty thousand years ago, the last great ice age buried the northern half of Europe under a
• hurricane (hurricanes)
NOUN A hurricane is an extremely violent wind or storm.
■ In September 1813, a major hurricane destroyed US gunboats and ships that were defending St Mary’s, Georgia, from the British.
■ Around eight hurricanes are predicted to strike America this year.
• typhoon (typhoons)
NOUN A typhoon is a very violent tropical storm.
■ large atmospheric disturbances such as typhoons
■ a powerful typhoon that killed at least 32 people
Hurricanes have heavy rains and are therefore more likely to cause floods. Droughts occur when there is a lack of rainfall.
Hurricanes and typhoons are both violent storms that develop over water. If the storm develops in the Atlantic or Caribbean it is referred to as a hurricane. If it develops in the Pacific, it is known as a typhoon.
The largest glaciers in the world are found in the polar ice caps of Antarctica and Greenland. Glaciers are also found in mountains.
A current is a steady flowing movement of air or water.
Sentence a: In freezing temperatures, water turns into ice and expands.
Sentence b: Metal, on the other hand, contracts when cold.
Sentence a: It is highly likely that glaciers will continue to melt.
Sentence b: It is unlikely that they will melt as quickly as some climate experts had predicted.
Sentence a: Previous predictions were based on inaccurate data.
Sentence b: More accurate information is now available.
Sentence a: Some climate scientists may have overestimated the rate of global warming
Sentence b: Others may have underestimated the impact of climate change.
In today’s talk I’m going to give you an overview of the most recent thinking on climate change. Recently the IGPCC – the Intergovernmental Panel on Climate Change – has conducted a major review of the evidence for climate change. In its conclusions, it states that the evidence for global warming continues to be overwhelming. However, according to the panel, some of the risk factors identified in earlier reports have been overstated, whereas other impacts of global warming may have been understated. In this talk, I’m going to outline some of the overstated risk factors and explain the current position on each. I’ll then mention briefly some of the aspects of global warming that are now considered to be a more serious problem than previously thought.
One of the most significant revisions in the new report concerns estimates of rising sea levels. Previous studies had predicted that sea levels would rise by more than two metres. The latest evidence suggests that sea levels are likely to rise by no more than one metre. This is good news for many coastal areas as flood defences currently in place are much more likely to cope with a rise of one metre. A rise of two metres would have required major investment in flood defences.
The reason climate scientists have come up with such different predictions of sea level rises has to do with our understanding of what is happening to the major glaciers and ice sheets around the world. Some appear to be contracting faster than predicted, and others appear to be expanding. In 2007, for example, the I6PCC predicted that the Arctic would be ice free in summer by 2080. The latest predictions bring this date forward by 20 years to 2060. In the Antarctic, on
the other hand, the ice sheet appears to be expanding as sea water freezes over. This variability in ice sheet activity accounts for the differences in our predictions of rising sea levels.
Another significant revision of our understanding of climate change concerns the Gulf Stream. As many of you probably know, the Gulf Stream is a current of warm sea water that travels from
the tropics northeastwards across the Atlantic. It is responsible for keeping temperatures in Europe and North America 5-10 degrees warmer than they would be otherwise. An earlier study concluded that the flow rate of the Gulf Stream had decreased by 30 per cent since the 1950s. It warned that the northern hemisphere could be heading for another ice age, in other words, a period of prolonged cold. However, a more recent study has indicated that currents of warm water have actually accelerated in the last 20 years. Climate scientists now believe that these differences are due to natural variability and that the Gulf Stream is unlikely to disappear. This is good news for those who live in Europe and North America.
I’d like to move on now and mention some of the consequences of global warming and some of the risk factors which may have been underestimated by previous studies. As far as consequences go, there is new evidence that tropical forests are more susceptible to drought than previously thought and that the severity of severe weather events such as hurricanes and typhoons may have been underestimated in the past. This is particularly bad news for those who
live in southern regions. More worrying, there is stronger evidence that thawing permafrost in northern regions is producing very high emissions of methane gas. As I explained in an earlier lecture, methane is a much more potent greenhouse gas than carbon dioxide. This thawing ground has the potential to significantly exacerbate climate change. I therefore have to conclude this talk by saying that, in spite of the good news on rising sea levels, global warming continues
to be a serious cause for concern. To ignore it would be most irresponsible.