Ten quickies about climate change

These ten facts about climate and climate change have been written by Jan Gunnar Winther, the Director of the Norwegian Polar Institute and a climate researcher.

1 - Weather versus climate

Weather is variations over short periods, whereas climate is changes in the weather situation over many years. The climate can be said to be the average weather over a long period. Consequently, it is impossible to link isolated episodes of outstanding weather situations, like a cold, snowy day in Tromsø in May or record high temperatures in Svalbard, directly to climate change.

2 - The climate has always varied

Yes, the climate varies naturally on both long time scales (ice ages versus interglacials) because of the position of the earth relative to the sun, and over short periods due to the dynamics in the ocean and the atmosphere which causes storms, extreme precipitation and floods. However, the changes in climate we are now experiencing are very rapid compared with those which have occurred in historic time, and the pattern suggests that our emission of greenhouse gases goes a long way towards explaining this.

3 - The CO₂ content in the atmosphere and the temperature have been higher previously

Yes, there have been periods with higher temperatures if we go millions of years back in time, but the astrophysical and climatic conditions were entirely different then. For instance, the continents were in completely different positions. Scientists have reliable data which show that the atmosphere now has 30 % more CO₂ than it has had during the interglacials in the past 700 000 years.

4 - Water vapour is a more important greenhouse gas than CO₂

Yes, water vapour contributes about three times more to the greenhouse gas effect than CO₂. However, the most important difference is that whereas water vapour occurs naturally in the atmosphere, human-induced CO₂ emissions give a greenhouse effect in addition to that which is natural.

5 - Human-induced CO₂ emissions account for only 1-2 % of the annual, natural CO₂ cycle

That is correct, but because of its slow breakdown, CO₂ accumulates in the atmosphere so that the atmosphere now contains 30 % more CO₂ than it did before the Industrial Revolution. In addition, the oceans gradually lose their ability to absorb CO₂ as the water becomes warmer, a so-called positive feedback loop that intensifies the warming.

6 - The sun controls the earth's climate

The sun naturally has a crucial effect on the earth's climate. However, present-day global climate models which predict the trend of the climate make allowance for the contribution from variations in the intensity of the sun, and it is far from sufficient to explain the warming that is observed.

7 - The research results differ substantially

It is by no means unusual that research produces results that differ. The global trend can only be studied when a wide range of research results, including local and regional studies, is compiled. Many climate researchers are surprised at the speed at which the changes in climate have occurred. The results of recent research indicate more rapid global warming than was envisaged only 5-10 years ago.

8 - Climate researchers disagree

Time and time again, it is claimed that climate researchers disagree strongly as to whether we are currently experiencing human-induced changes in climate. In reality, only a very small minority of them question human-induced changes in climate and the debate among the vast majority concerns what proportion of the changes are man-made – not whether they exist.

9 - The IPCC

It is claimed that the Intergovernmental Panel on Climate Change (IPCC) is composed in such a way that sceptics do not have a say. Some go so far as to imply a conspiracy. The panel consists of more than 2000 highly competent scientists. Researchers who have contributed most through quality-assured scientific work are invited to be authors on the climate panel; in other words, the experts among the experts. In addition, the reports published by the panel are quality assured by a large number of independent experts, so-called ”reviewers”.

10 - Little Norway makes no difference

It is correct that Norway's emissions amount to only a small proportion of the world's total emissions. But how can the global climate challenge be tackled if the responsibility is split up so that no nation sees any point in contributing? Or what if China or the USA claimed that every single province or state makes such a small contribution that it makes no difference? Quite the contrary, filthy rich Norway should be at the forefront to show the world the way. A nation that produces only a small percentage of the global emissions of greenhouse gases can have great influence by leading the way with regard to future-oriented energy production and utilisation.