Some impacts of global climate change were already being seen in Europe and others were projected to happen over the coming decades as global temperatures continued to rise, a new report from the European Environment Agency states.
The report says that such impacts include more frequent and more economically costly storms, floods, droughts and other extreme weather.
Wetter conditions in northern Europe but drier weather in the south could threaten agriculture in some areas and more frequent and more intense heatwaves posed a lethal threat to the elderly and frail. Melting glaciers, 75 per cent of which were in the Swiss Alps, were likely to disappear by 2050, raising sea levels for centuries to come.
The report said that strong evidence existed to show that most of the global warming over the past 50 years was caused by human activities, in particular emissions of heat-trapping greenhouse gases such as carbon dioxide (CO2) from the burning of fossil fuels.
The concentration of CO2, the main greenhouse gas, in the lower atmosphere was now at its highest for at least 420,000 years - possibly even 20 million years - and stood 34 per cent above its level before the industrial revolution. The rise has been accelerating since 1950.
The report pointed out that the serious flooding in 11 countries in August 2002 killed some 80 people, affected more than 600,000 and caused economic losses of at least US$15 billion. In the heatwave of last summer, Western and Southern Europe recorded more than 20,000 excess deaths, particularly among elderly people. Crop harvests in many southern countries were down by as much as 30 per cent and melting reduced the mass of the Alpine glaciers by a tenth in 2003 alone.
"This report pulls together a wealth of evidence that climate change is already happening and having widespread impacts, many of them with substantial economic costs, on people and ecosystems across Europe," Jacqueline McGlade, EEA executive director said.
She added: "Europe has to continue to lead worldwide efforts to reduce greenhouse gas emissions, but this report also underlines that strategies are needed, at European, regional, national and local level, to adapt to climate change. This is a phenomenon that will considerably affect our societies and environments for decades and centuries to come."
The extent and rate of the climate changes under way most likely exceeded all natural variation in climate over the last 1,000 years and possibly longer. The 1990s were the warmest decade on record and the three hottest years recorded - 1998, 2002 and 2003 - have occurred in the last six years. The global warming rate was now almost 0.2°C per decade.
Europe was warming faster than the global average. The temperature in Europe rose by an average of 0.95°C in the last 100 years and was projected to climb by a further two to 6.3°C this century as emissions of greenhouse gases continued building up.
As a first step towards reversing this trend, the world's governments in 1997 agreed on the Kyoto Protocol, an international treaty under which industrialised countries would reduce their emissions of six greenhouse gases by around five per cent between 1990 and 2012.
So far, 123 countries, including all EU member states, have ratified the treaty but the US, the biggest emitter of greenhouse gases, has decided against doing so. To enter into force the protocol still needs ratification by Russia.
The report says that almost two out of every three catastrophic events since 1980 have been directly attributable to floods, storms, droughts or heatwaves.
The average number of such weather and climate-related disasters per year doubled over the 1990s compared with the previous decade.
Economic losses from such events have more than doubled over the past 20 years to around US$11 billion annually. This was due to several reasons, including the greater frequency of such events but also socio-economic factors such as increased household wealth, more urbanisation and more costly infrastructure in vulnerable areas.
The annual number of floods in Europe and the number of people affected by them were rising. Climate change was likely to increase the frequency of flooding, particularly of flash floods, which poses the greatest danger to people.
Climate change over the past three decades caused decreases in populations of plant species in various parts of Europe, including mountain regions. Some plants were likely to become extinct as other factors, such as fragmentation of habitats, limited the ability of plant species to adapt to climate change.
Glaciers in eight of Europe's nine glacial regions were in retreat, and at their lowest levels for 5,000 years.
Sea levels in Europe rose by between 0.8 and three millimetres per year in the last century. The rate of increase was projected to be two to four times higher during this century.
Projections show that by 2080 cold winters could disappear almost entirely and hot summers, droughts and incidence of heavy rain or hail could become much more frequent.
However, climate change also appeared to have some positive impacts - not for southern European countries, but for those in the centre and in the north.
Agriculture in most parts of Europe, particularly the mid-latitudes and northern Europe, could potentially benefit from a limited temperature rise.
But while Europe's cultivated area may expand northwards, in some parts of southern Europe agriculture could be threatened by water shortages. And more frequent extreme weather, especially heatwaves, could mean more bad harvests.
The annual growing season for plants, including agricultural crops, lengthened by an average of 10 days between 1962 and 1995 and was projected to continue getting longer.
The survival rate of bird species wintering in Europe has improved over the past few decades and was likely to increase further as winter temperatures continued to rise.
The report "Impacts of climate change in Europe: An indicator-based assessment", is available online.
http://reports.eea.eu.int/climate_report_2_2004/en