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Thaw point

February 2005

Is Antarctic ice melting faster? Is the world getting warmer? Is the world changing for the worse? Will we be eating jellyfish and chips?

Thaw point

The newspapers are currently packed with climate change stories. Scenarios of an ‘ice-free’ world that is 11ºC warmer than today have been jostling for column-space with protests from climate change deniers. Almost a year on from our last Geography in the News round-up and, on the eve of the day the Kyoto Agreement comes into force, we summarise some of the more newsworthy recent global warming stories.


Is the world really changing for the worse?

A new conference on climate change has revealed findings which show that climate change is speeding up and that its effects may be worse than has hitherto been suspected. As we reported in our Antarctica In-depth report, the world’s biggest iceberg, B15, broke away from the Ross Ice Shelf that surrounds part of Antarctica in March 2000. Two hundred feet high and the size of Jamaica, it split in half in October 2003 (The Guardian, 15 November 2003). Early reports suggested that the surrounding mass of sea ice had shrunk by 20% in the last 50 years but that the overall situation was unlikely to worsen very rapidly.

Now it appears that changes in Antarctica are accelerating at an alarming pace. The conference, held in Exeter, was told that “the giant is awakening” (The Guardian, 02 February 2005). The loss of parts of the ice shelf, which floats on the sea surrounding Antarctica, does not in itself greatly effect sea levels. However, land-based glaciers that have been impounded behind the ice sheet are now starting to slide into the sea. Given that 70% of the earth’s fresh water is stored as ice on the continent of Antarctica, there is a clear threat of global eustatic sea level rises as these glaciers surge forwards into the sea and begin to melt.


Are we really going to get 11ºC warmer?

The Times (27 January 2005) reports that the impact of global warming could be twice as severe as the worst scenario previously feared. Average temperatures could rise by 11C (20F) according to researchers who have run 60,000 computer simulations of climate change. A world so much warmer than today such as this would be almost unrecognisable. Although it would take hundreds of years for the full effects to be felt, the polar ice caps eventually would melt completely, causing sea levels to rise by between 70m and 100m, submerging coastal and low-lying cities such as London and New York. The results, published in the journal Nature, have emerged from www.climateprediction.net, an experiment in which spare capacity on personal computers runs climate models.

Top 4 warmest year worldwide since 1890s

The Fourth Warmest Year in a Century

1. 1998

2. 2002

3. 2003

4. 2004

Credit: NASA GSFC/LARC and SVS

2004 was the fourth warmest year around the world, since the late 1800s, according to NASA scientists. 1998, 2002 and 2003 were the only years warmer since the 1890s.

But is the prospect of a radical change in temperature science fact or science fiction? Evidence from a new study by the Woodland Trust appears to give support to the latter view by concluding that temperatures in Scotland are already changing beyond all recognition as a result of global warming. Midwinter in Scotland now resembles the south coast of England 10 years ago, say the report’s authors. The Sunday Times (06 February 2005) explains that “timings of when particular flowers bloom show that spring arrives in Scotland two weeks earlier than it did 30 years ago, and 2005 may be the earliest ever. Spring in Scotland is now a full month earlier than it was in 1920, and the trend is accelerating”.

The Independent (06 February 2005) is more concerned that the spectre of drought is becoming a permanent menace facing the east of Britain as temperatures are raised and atmospheric circulation patterns modified. The paper suggest that “scorching summers will become increasingly frequent with global warming, with very hot Augusts - such as in 1995 - happening once every five years by 2050. Less rain will fall, and more moisture will evaporate from the soil, causing droughts.” In contrast, winter rain might increase in the UK, due to increased rates of evaporation during the summer. Rivers may reach bankfull discharge more frequently and there will be more localised flood disasters such as those seen recently in Boscastle and Carlisle (see ‘Many unhappy returns’ on return periods of these kinds of events).

In “compensation” for these inconveniences, The Independent notes that a hotter Britain is likely to be able to grow more of its own wine! Farmers could reap further short-term benefits from global warming as the growing season increases, while higher levels of carbon dioxide in the air may encourage more vigorous crop growth.


Controversial advantages of a warmer world

The Guardian (03 November 2004) outlines some possible short-term advantages of a warmer world. These are controversial and need to be weighed against the potential losses that communities and ecosystems would face. What additional advantages can you think of in addition to those listed below? What likely disadvantages would offset these gains?

  • Oil and gas deposits under ice and permafrost would be easier to reach
  • More farming could be possible in high latitudes such as Alaska
  • Short-cut trans-Arctic shipping routes could shorten the journey from Japan to the UK by nearly 12 days
  • More wine grown in the UK


Will the Gulf Stream really get diverted?

We reported last year that scientists were becoming increasingly concerned about the possibility of the Gulf Stream being diverted, leading to the cooling of the UK (see Professor Bill McGuire’s report in The Guardian, 13 November 2003). The recent conference on climate change has said that the chances of this occurring are now almost fifty-fifty. The Gulf Stream is an ocean current that brings warm waters to areas of the North Atlantic such as the UK. Without it, scientists warn that temperatures could actually fall by 10 degrees Celsius and coastal waters might freeze up in the winter (The Guardian, 02 February 2005). In addition, vulnerable cold-loving species, such as polar bears and penguins, may become threatened with extinction (The Daily Telegraph, 02 February 2005).

The Gulf Stream current – also known to oceanographers as the Atlantic thermohaline circulation – carries one billion watts of heat annually from the tropics to the Arctic via Scotland. It has recently been weakened by 10% and scientists warn that a 3C rise in global temperatures – which is well within current predictions – would bring a 45% chance of complete shutdown. This is because patterns of ocean circulation will be modified by warmer air temperatures as well as by huge inputs of cold glacial meltwater from the Antarctic. The resulting climate could be even colder than Europe experienced in the 1600s, during the so-called “Little Ice Age” when the Thames regularly froze over in winter.


Is house-building looking like a really bad idea?

In a related story, The Guardian (01 February 2005) reports that the insurance industry has said the UK government's plans to build 85,000 homes in the Thames Gateway must be modified, due to the increased threat of flooding that climate change is bringing. Safeguards will be needed, such as allowing people to only occupying homes above first-floor level. Ground floors should be reserved for car parking or low-risk storage, a feature that can already be seen in some flood plain housing, notably in Bewdley along the River Severn.

The report follows repeated Environment Agency warnings that local planners are ignoring its advice not to build on the flood plain, which could be financially damaging for an insurance industry that is still recovering from the cost of nationwide flooding in 2000. Now, the Association of British Insurers (ABI) says the Thames Gateway developments will be uninsurable unless new measures are taken to minimise the flood threat. Without insurance, home-buyers cannot get a mortgage, a situation which would seriously jeopardise the government’s housing plans.

According to the ABI, the government’s flood risk assessment of the newly planned Gateway settlements takes no account of climate change. As a result, estimated return periods for extreme flood events have been underestimated and the likelihood of insurers having to make enormous pay-outs is much greater than the government is claiming (see return periods article). Although much of the south-east supposedly has a 1:1000 level of protection, climate change means that the level has probably fallen to about 1:100 in many areas. This means that there is a 1% chance in any year of severe flooding in the proposed new housing growth area. This is not a level of risk that insurers are happy with. Similar concerns have recently been aired by the British Antarctic Survey in a report that warns of London being swamped by much higher sea levels in the not-too-distant future (The Times, 02 February 2005).


Will we really be eating jellyfish and chips?

The latest new threat that climate change is bringing is increased acidity in the oceans. Extra carbon dioxide in the air, released by the burning of fossil fuels, is mixing with ocean water to form mild carbonic acid. Half of the Carbon Dioxide released since the start of the industrial revolution in 1750 is thought to have been soaked up by the sea in this way (The Guardian, 04 February 2005). This is now thought to be the cause of an increase in sea water acidity from pH 8.2 to 8.1 (indicated here by a slight reduction in pH level). In some waters, notably around the UK, acidity is even greater due to Europe’s high level of carbon emissions. If the fall continues, then growth rates in plankton might be reduced. Plankton forms the base of the marine food chain and any reduction in numbers will ultimately reduce the numbers of fish such as cod. However, jellyfish might prosper under the changed conditions as they do not feed on plankton. As a result, The Guardian newspaper suggests that the British might have to change their national dish from cod and chips to jellyfish and chips.


Or is climate change just a myth?

Climate change is not yet a universally accepted truth although, thanks to research, it's getting more and more difficult to argue that our climate isn't changing, according to Eliza Cook in the magazine of the Royal Geographical Society, Geographical (March 2005). However, a conference last month disputed many of the conventionally accepted facts about global warming. Is it possible that the experts have got it wrong? We know that Europe experienced the “Little Ice Age” in the 1600s, so could a similar natural fluctuation be occurring today? From a UK perspective, might a rise in air temperatures be offset against the cooling that a weakening of the Gulf Stream might bring, leaving us with nothing to worry about? With so many variables to consider, can we really make accurate predictions of change?

Climate change sceptics believe that the threat of global warming has been greatly over-exaggerated and that war and disease are the problems that humanity should really be engaging with. The Guardian (28 January 2005) summarises a few of the sceptics’ arguments, noting in particular the assertion that “carbon dioxide is plant food and makes them grow faster”. Increased Carbon Dioxide may simply be absorbed by plants, leaving air temperatures relatively constant. Rises in sea level, where already observed, are said to be more likely to be attributable to local factors, such as subsidence, rather than to a global rise in sea level.

However, the sceptics are in an ever diminishing minority. Increasingly, it appears that the world’s scientific community is reaching a consensus on the problems of global warming and the human use of fossil fuels. Even the National Geographic magazine – with a notoriously conservative readership – has recently presented the case for global warming and climate change as an unassailable “fact”. The September 2004 edition of National Geographic is well worth seeking out – it contains a brilliantly-illustrated and highly informative series of global warming articles, as well as a controversial editorial.


Further reading

  • Our previous climate change round-up, published in May 2004, is available
  • Read the September 2004 edition of National Geographic.
  • February 16 2005, the Kyoto Agreement comes into force – geography students should keep a lookout for special features in the newspapers and on television.

Themes

Global warming & climate change

Human activity modifies physicalsystems

Physical changes modify human systems

Tips for GCSE & AS candidates

When writing about sea-level rise, there are two important errors to avoid:

(1) Do not imagine that all of the UK is at increased risk of flooding. Due to complex past geological events, the south of England is sinking but the north of Scotland is actually rising out of the sea at about 4mm per year! As a result, the effects of sea-level rise will be much worse in the south. Remember also that flat, low-lying land can stretch far inland along the lower course of a river’s floodplain. Consequently, some areas a long way inland (like London) are potentially at risk of flooding if global sea levels rise.

(2) Do not suggest that global warming will result in a Biblical-style catastrophe, with floods sweeping away cities and drowning millions. Remember that these changes will take decades to occur and are more likely to lead to the progressive abandonment of sea-front areas of towns and cities as floods get more frequent and people can no longer get insurance for their houses. Occasional violent storms will cause some deaths, but there will not be a great catastrophe where masses drown such as that depicted in the “The Day After Tomorrow”!

AS/A2 exam tips

Change and modify…. or kill and destroy?

Most A-level students will be asked to comment upon how physical or human geography is being changed or modified by climate change at some point during their two-year course. Unfortunately, all too many take ‘change’ and ‘modify’ to mean ‘destroy’ and write at length about catastrophic scenarios - where people are imagined to drown and animals and plants will die – without having any real evidence to back up such extravagant claims.

Examiners are looking for a much more sophisticated understanding of the kind of changes that can occur in a system when its natural equilibrium is disrupted. For instance, a warmer earth is not necessarily one where mass extinctions will take place. However, there are certain to be changes in the current distribution patterns of animals and plants. While deserts may grow in some areas, making land unproductive, it is also possible that unproductive cold areas will develop a longer growing season and that animals and plants will migrate into new areas of Canada and Russia

If asked to comment on the “impact” of climate change, try to carefully “unpack” a series of contrasting types of effects that this may have on the environment. It would be advisable to incorporate at least two different interpretations of “impact” into your answer. In the case of climate change, local impacts (falling revenues for ski resorts in the Alps) and global impacts (worldwide shifts in vegetation distributions or migratory paths of animals) might be a useful approach to take.

Also, try to remember that changes to the physical environment do not necessarily impair or damage its ability to function as a system. The most common cause of mediocre performance amongst students writing about the environment is to lazily suggest that human activity simply destroys physical systems. Look instead at how the size of flows and stores might change. A good example might be the basin hydrology and regime of a small river in southern England. What kind of changes might generally warmer temperatures but greater incidences of severe storms bring to the dynamic equilibrium of the typical catchment? How would this effect soil water stores during the course of a year, for instance?

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