A relative concept

The impact of climate change is relative; it will have very different consequences in different parts of the world.

The differences are not just about the impact on places; the influence of wealth also has a part to play.  Richer people [and countries] are more likely to be able to pay to adapt to climate change than poorer people.  They may be able to move to a safer place or change particular aspects of their lives to adapt to the changes around them.

One example of this is the impact of Hurricane Katrina [August 29th 2005] on the people of New Orleans in the USA.  The US government estimates that the hurricane-force winds were experienced by 5.8 million people and contributed to the deaths of more than 1000 people.

Major damage was caused by severe winds and a very high surge of water which broke through flood defences.  The US government states that the hurricane had varying impacts on the population, with the poor being disproportionately affected.  They estimate that 20 per cent of those people who had to leave their homes due to storm damage or severe flooding were poor, with 30 per cent living below the poverty line.

They state that:

‘Some who lived in the areas most impacted by the storm may now be destitute; while having managed financially before the storm, in the storm’s aftermath they may have joined the ranks of the poor.’

This may mean that these people will find it extremely hard to find the money to rebuild houses.  They may also have lost jobs.

Local variation

People’s own local knowledge is a good signal of change and many major climate change reports are based on gathering together data recorded at a local level.  This might include weather data, photographs of natural features [such as glaciers] or recording changes in plant and animal behaviour each year [phenology].

The Royal Botanical Gardens at Kew in London has studied 100 plant species over 50 years to see how they are responding to changes in temperature.   Their results have found that over 75 per cent of the plants have shown significant changes in their growth patterns, particularly since the 1980s.  In some cases common flowers were coming into bloom several months earlier than normal.  Similar patterns have been recorded at botanical gardens in China, Japan and the USA too.

By combining these local reports, a global picture of change begins to become clearer, but we need to think carefully about what the data is really showing us. When reports use global averages, the whole range of data that has actually been collected is not shown.  This could give the impression that the situation is better or worse than it actually is.  Being able to ask questions about data and patterns improves our ability to make choices.

Regional variation

Data and information about climate change [such as predicted temperature, sea levels, rainfall] often refer to the global scale and can hide enormous differences across regions and countries.  For example the International Panel on Climate Change [IPCC] says:
dot  The predicted increase in average temperatures by 2100 range from as little as 0.4ºC for New Zealand to as high as 10.5ºC for northern Asia.

Studies of the impacts on whole continents also hide considerable differences as they do not take account of altitude, terrain, vegetation, and local climatic conditions (wind, cloud cover etc).  The map of Australia below shows how these factors might alter predicted temperature increases.  The drier, desert interior might experience a greater temperature increase than the cooler coastal climates.  For snow and rainfall, the differences are even more localised and difficult to predict.

Rising seas

One of the most well known predictions made by the International Panel on Climate Change [IPCC] is an increase in average sea levels:

  • Between 1961 and 2003, global sea levels rose by an average of 1.8 mm per year.
  • Between 1993 and 2003, they rose at 3.1 mm per year - almost twice as fast.

Sea levels alter naturally, but most scientists agree that climate change [influenced by human activity] is now a major cause and could lead to an increase in sea levels of between 0.20m and 0.59m by 2100. An increase of 0.5m would flood around 1800 km2 of the fertile Nile Delta in Egypt, forcing approximately 3.8 million people to find somewhere else to live.

Climate change can lead to sea levels rising for a number of reasons:

Expanding water

  • As water increases in temperature it expands to take up more volume in a process called thermal expansion.  The IPCC reports that up to 80 per cent of the heat added to our climate system so far has been absorbed by the oceans, so the oceans are already expanding.

Melting ice

  • Warmer temperatures can cause glaciers, snowfields, ice caps and polar ice sheets to melt.  As the water stored within them is released, a large amount will find its way into the oceans.

Coffee production

Coffee is enjoyed by people around the world, but grown in just a few tropical countries with the right combination of soils, altitude, rainfall, temperature and sunlight.

For some countries, producing coffee is a vital part of their economy.  Selling to other countries brings in important foreign money and provides many jobs.

Uganda, in East Africa is a good example.  It produced 2.75 million bags of coffee in 2007, a large proportion of which were sold abroad.  The country is therefore very dependent on growing and selling coffee to other countries.

This dependence on coffee is now under threat from climate change.  A recent report from the United Nations Environment Programme predicted that a 2ºC increase in average temperatures would have a major effect on coffee production as it needs very particular growing conditions.  The map below shows the dramatic reduction of areas suitable for growing coffee if the temperature does increase as predicted.

Uganda would no longer be a major coffee producing nation and its economy would be severely affected.  If other coffee growing regions around the world suffered from a similar problem, one of the world’s most popular drinks would become very difficult to grow and sell, and millions of coffee growing farmers worldwide would be affected.

Kyoto protocol

The Kyoto Protocol is the shortened name for an international agreement for countries to reduce their emission of greenhouse gases [including carbon dioxide] by 5 per cent of their 1990 levels by the year 2012.

The idea of an international agreement was first suggested in 1992, and was finally adopted at a meeting in Kyoto, Japan in 1997.  It took another eight years before it finally came into force in 2005.  The eight year delay was caused because each country had to agree the targets with their own national governments before the final agreement could be signed.

Many people are critical of the Kyoto Protocol because it allowed the world’s largest producer of greenhouse gasses [the USA] to pull out of the agreement in 2001.  They are also critical of the time it has taken to come into force and argue that the 5 per cent target is far too low.  In fact some scientists have said that a target of nearer 60 per cent would be needed to have any real impact.

The next phase of international agreements will be debated at the United Nations Climate Change Conference in Copenhagen in December 2009.

Temperature recording & climate change

The longest record of changes in atmospheric temperatures anywhere in the world is the Central England Temperature record in the UK.  Scientists there have been recording temperatures since 1659, making the data one of the world’s most reliable indicators of climate change.

According to their records so far, 2006 was the hottest year ever recorded at 1.37ºC warmer than the average for the 30-year period 1961-90.  More importantly, according to the data nine of the ten hottest years recorded by the data have happened since 1989.

Some believe this information shows a pattern of global warming, but others warn that it may just be a short period of slightly higher temperatures.  What do you think?

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