Global warming or climate change?

We got about four inches of snow over Luton last night, and judging my the number of stranded cars on Luton’s hills, nobody has really learnt anything from last winter. Just like in January, the arrival of snow has been greeted with clapping and cheering from the climate sceptics – isn’t it funny that it’s snowing while the Copenhagen summit is on?

It being mid winter, no, it’s not especially odd that it’s snowing. Far more interesting is how people can miss the wood for the trees, pointing to isolated weather events and not noticing the accumulating evidence of a destabilising climate. (There’s another one in my garden right now. I planted three fruit trees last weekend, and the winter has been so mild so far that one of the apple trees was in blossom in December. The poor confused little sapling is now covered in snow.)

There are good reasons why responsible climate scientists talk about ‘climate change’, rather than ‘global warming’*. As the earth warms, the delicate balances of our climate systems go awry, making weather increasingly extreme and unpredictable. Change is not linear, so some countries have had record highs and lows in the same year, or both floods and droughts. The US and Canada have been mildly colder than average, but still saw the hottest Alaskan summer temperatures on record. South America saw an unseasonally warm October, immediately followed by an unusually cold November.

Australia has had a string of record heatwaves, with temperatures hitting a sweltering 48.8C. The country is still in a nine year drought, but still saw flooding in the autumn. India’s monsoon season saw so little rain that 40% of the country experienced drought, only to suffer floods after relentless rain in September.

Elsewhere, China has had its third warmest year and its worst drought in 50 years. Germany had new high temperature records in the Spring. Scandinavia, on the other hand, had a particularly cold October. Here in the UK we had heavy snow in January and February, and a new rainfall record in November for the most rain in 24 hours – 314.4 mm in Seathwaite on Nov 24th.

The hurricane season has been a little quieter than usual, which was expected. Less expected was winter storm Klaus, which swept through France and Spain in January and caused billions of euros of damage. Canada had a very bad year for avalanches and a record number of tornadoes. Turkey recorded its highest September rainfall and flash-floods to go with it. Arctic sea ice has been at its third lowest recorded extent, and although local Russian companies have been able to use it occasionally, the North-east passage was considered commercially viable for a western shipping company for the first time.

Despite the endlessly repeated claims that the world hasn’t warmed since 1998, when you put it all together this has been the warmest decade on the instrumental record:

*Many sceptics read a plot into this: scientists used to talk about global warming, and then when it became apparent that the world wasn’t warming, it was conveniently changed to ‘climate change’. In fact, the UN formally adopted ‘climate change’ as its term of choice back in the 80s, naming their scientific body the Intergovernmental Panel on Climate Change in 1988. It was chosen specifically because it was less likely to cause alarm, and because climate change takes many forms. Rising heat overall could cause some areas to end up colder, if sea currents change and so on. The climate is also destabilised, causing droughts, floods, and storms. In fact, ‘climate change’ is a more honest term, and less ‘alarmist’ than ‘global warming’, so it’s odd that sceptics prefer the latter.

• PS – if you saw the Daily Express’ headline this week 100 reasons why climate change is natural, you may be interested in the New Scientist’s reply to the first 50. You’ll see why they stopped halfway. It’s pretty repetitive.