Towards a sustainable York is about taking local action to tackle global issues. There are a number of existing and emerging issues which are of global significance and which will require a co-operative and co-ordinated international response. These include:

• climate change
• ozone depletion
• use or resources
• nitrogen loading
• chemical risk
• natural disasters
• degradation of land, forests and bio diversity
• availability of freshwater
• marine and coastal areas
• air pollution
• urbanisation
• poverty
• world trade

Find out more about global issues on the Met Office website, on the Greenpeace website and on the Friends of the Earth website. The council is not responsible for the content of external websites.

Climate change

Every time severe weather strikes, global warming seems to be blamed.

But what is it and should we be worried? These pictures, from the Met. Office show the global temperature change from 1900, predicted for 2000 and 2090; they show how the average temperature of the earth could rise. What is particularly interesting is the rate of change. The change between 1900 and 2000 is relatively small compared to that between 2000 and 2090, and it is in that later period that most of us will spend our lives.

There are many reasons given for global warming, and these include the fact that the earth goes through cyclical changes of temperature, illustrated by previous ice ages, however, few people now dispute that the effects of climate change are being accelerated by our actions as human beings.

Greenpeace says that 'Greenhouse gases, mainly carbon dioxide (CO2) from burning oil, coal and gas for energy, are altering the composition of the earth's atmosphere and causing global temperatures to rise resulting in floods, storms and droughts wreaking havoc around the world.'

Records show that the average temperature of the planet is climbing quite rapidly, and in Britain, 1998 proved to be the hottest year in the last thousand years. Although the global weather system is extremely complex and not wholly understood, most experts agree that rapid changes in temperature are bound to have severe implications for future weather and climate patterns.

Sea level rise

One of the most threatening effects of global warming is the effect it could have on sea levels; the global sea level has risen by between 10 and 25 cms over the last century, as glaciers melt and warming sea water expands, and levels could rise by another 15 to 95 cms by 2100, and they will
probably go on rising for 500 years because the oceans have only just begun to warm up. If these predictions are correct, the rate of change over the last two to three centuries will have been greater than at any other time in the last 10,000 years.

Global warming

Many scientists believe recent global warming has been generated by human influence on a naturally-occurring phenomenon called the greenhouse effect:

The sun's energy heats the surface of the earth, although some of that heat is radiated back into space and the planet cools, however, some gases in the atmosphere, called the greenhouse gases, prevent this and so trap the heat. Since the Industrial Revolution, humans have been pumping out huge quantities of greenhouse gases, most notably carbon dioxide.

Before 1850 human activity had little influence on the amount of carbon dioxide in the atmosphere, but since the industrial revolution concentrations of carbon dioxide, methane, nitrous oxide and
chlorofluorocarbons, or CFCs, have greatly increased. Burning fossil fuels is seen as being responsible for most of the increase in carbon dioxide.

The consequence of all of this is that general warming is expected to lead to an increase in the number of extremely hot days and decrease in the number of extremely cold days. Warmer temperatures will lead to more severe droughts and floods in some places, and because rapid climate changes are unpredictable may lead to some "surprises" and even if people are able to adapt to climate change, many animal species will not. For vegetation the prospect is even worse as plants and trees will not be able to migrate fast enough to find new habitats as the climate changes encroach on their existing territory.

Another thought to ponder is the effect of the Gulf Stream on Britain. This warm sea current flows up from the Gulf of Mexico across the Atlantic, to flow against the west coast of Britain; this moderates the temperature in Britain, stopping us experiencing the same winter temperatures as other countries at the same latitude. York, with its usually warm summers and not too cold winters, lies as far north as Canada and Siberia; it is possible that global warming could divert the Gulf Stream away from the British coast, leaving us with winters more like those experienced by other countries that lie this far north.

The future and what can we do?

Future trends may depend on action that humans take to modify their activities. Both scientists and environment campaigners say human impact on the climate can be reduced by a number of measures:

We could reduce energy consumption by making fewer journeys and by using better insulation in our homes. This would lessen the need to burn petrol, diesel, coal and oil, and lead to reduced emissions of carbon dioxide and nitrous oxide.

Advances in technology could result in fossil fuels being burned more efficiently.

Emissions could be reduced by making wider use of low carbon fossil fuels like natural gas, and decarbonising exhaust gases from power plants.

We could switch to renewable and clean sources of energy such as solar, wind and hydro-electric power.

Sustaining existing forest cover, planting new trees and better management of land use is also suggested as a means to slow global warming.

What we are seeing now is the result of the greenhouse gases emitted up till about 1968, because it is estimated that the climate takes about 30 years to catch up with extra pollution already emitted. The damage our pollution today is causing will probably not become apparent till about 2030.

The recent flooding in York has been attributed by many people to changes in the climate. John Prescott, Deputy Prime Minister suggested that whilst statistics recorded the floods as a once in 500 year event, we should expect the type of weather that caused them more often; it could even happen again next year.

A question is whether the problems caused by the floods are the fault of the Council and Government for not providing adequate flood defences, or the fault of individuals and business for not paying enough attention to their own contributions to global warming ? It could be suggested that we all need to start to taking our own contributions to the problem in hand, and accept some responsibility for climate change! Go to 'Doing your bit' for tips.

More information about climate change visit:

• Intergovernmental Panel on Climate Change website
• Carbon Trust website
• Climate Ark website
• Extreme Weather Events website
• Rising Tide website