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The day
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Are we already living in the age of climate change?

The average temperature at the Earth's surface has risen by a global average of about 0.6°C during the last 100 years. It will increase further and even faster ...

Scenes from the film: The animals are anxious, birds escape from climate collapse ... something seems to be unusual in town ...

The world of animals and plants also indicates climate change in reality and birds have moved to other breeding areas. During the last 50 years bird migration and breeding has taken place earlier than before (about 2-5 days per decade). The budding and bloom of many plants has also been brought forward by the same range. The temperature trend of the last century points towards higher values and the main reasons are the sun and human influence.

Opponents of the greenhouse theory often argue that the increasing activity of the sun is the only reason for global warming. But a clear majority of scientists estimate this contribution to be below 25%, and human emissions are the dominant cause, particularly for the strong temperature increase of the recent decades.

Diagram on the right: How has temperature changed in the world during the last century? The graph shows the relative increase in °C. The zero value is the temperature average of the years 1961-1990. Grey shaded areas show the uncertainties.
Source: IPCC TAR 2001

The climate has a very long term memory. At the moment, we still emit far too much carbon dioxide to avoid a further increase in temperature. If we manage to reduce our emissions to about 10-20% of the present value during the next decades, the CO₂ value will stabilise on a high level. But temperature will increase further for a while, although more slowly. The huge water mass of the oceans will follow the warming of the air via surface exchange, but extremely slowly. Therefore, the sea level will not jump up but rise slowly and continuously. Scientists are working on climate model runs over centuries, but to give numbers would not be reasonable.

Can people have such a strong influence on the climate?

With respect to the scale of the expected climate change, you could ask, how humans could manage to have such an influence on the climate system. Looking back over 400,000 years of climate history (see also the image in the section 'abrupt climate change'), we see that there has never been a comparable amount of the greenhouse gas CO₂ in the air. It has been about 180 parts per million (= 180 ppm) in glacials and about 280 ppm during interglacials (warm times). Since about 8000 years ago we have been living in a stable interglacial time, but we now have 370 ppm of CO₂ in the air. We have brought such huge amounts of the gas to the atmosphere, because we burnt large quantities of carbon based resources, which have been formed by the life, respiration, growth and death of vegetation as coal, oil and natural gas over millions of years, within a few decades. From this burning of so called fossil fuels we gain our energy and the emissions go into the atmosphere. If we look 500 years back in time, it becomes obvious, that not only less people were living on Earth (about 500 Million), but that every single person also had a lot lower energy demands. All production was based on the physical strength of humans or animals. The invention of the fuel driven machine was the first step towards global warming.

There is no question that we are already living in the age of climate change.

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THE DAY AFTER TOMORROW offers a scenario that is rooted in real concerns about the state of our planet. "We pushed the time period in which an ice age could occur for dramatic purposes." says Mark Gordon, "but the theory that global warming could cause an abrupt climate shift is gaining mainstream attention. While nobody knows what the exact result will be of mankind’s addition of carbon dioxide into the atmosphere, some experts have referred to it as ‘the largest uncontrolled scientific experiment in history.’"