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A Most Surprising Season?

Posted: Friday 8th January 2016 by BrianEversham

Cowslips by Brian EvershamCowslips by Brian Eversham

Should we be amazed to see spring-like weather in winter? Not if we've been following the science, says Brian Eversham

New year, new blog. One of my (several) resolutions this year is to blog more often - and to do so with a stronger focus on natural history and the science underpinning it.

Over the holiday, weird weather, unprecedented floods and potential links to climate change have been in the news, with the warmest December for over a century measuring a clear 4°C above long-term averages. How is wildlife responding? Well, this morning at Cambourne, magpies were carrying twigs for nest-building, great tits were in full song, hazel catkins were dangling from branches, and lords-and-ladies leaves were unfurling. Bumblebees, solitary bees and a range of butterflies have been seen over the holiday, and slugs and snails are feeding, mating and egg-laying as they normally do in September or March; there’s no sign of hibernation or a winter lull in activity for so many species.

Because ‘spring’ flowers such as daffodils have been out in December, it’s hard to work out whether some plants are very early or very late. Twitter posts from around the country on the Botanical Society's #NewYearPlantHunt showed blooming primroses, cowslips, celandines, red campion, white comfrey, dandelions, lady’s-bedstraw, viper’s-bugloss, a range of speedwells, forget-me-nots and buttercups, yarrow, common centaury, ragwort and ivy-leaved toadflax - making it virtually impossible to work out what season we are in.

Journalists still attempt to present a ‘balanced’ view of climate change, giving equal time to the 3% climate sceptics alongside the 97% mainstream. Climatologists are naturally cautious about linking any individual event to long-term trends, which seems beyond the statistical understanding of much of the media, who prefer to imply that the current weather is somehow unexpected. This is ever-more frustrating because the settled view of world science is that climate change is happening and requires action now. This is not a new phenomenon: I remember hawthorn blossom and nesting long-tailed tits in January in the early 1970s. The famous hockey-stick graph of climate change shows an upturn from about 1900, and for the last 50 years mean temperatures have been even higher than the Medieval warm period - whether this historical trend is derived from documentary sources, from tree-ring analysis or from ice-core data.

I wrote my first paper on the effects of climate change on British invertebrates back in the 1980s. And I was a late-comer to the field - John Sawyer’s very clear paper, Man-made Carbon Dioxide and the “Greenhouse” Effect, appeared in Nature in 1972. Fifteen years later, I described the rapid northward spread of Roesel’s bush-cricket and long-winged conehead. In the subsequent 30 years, these species distribution trends have continued and those two bush-crickets are common across most of England. The effect has been enhanced by the colonisation of additional species of bush-cricket and dragonfly, such as the southern oak bush-cricket, large conehead and small red-eyed and willow emerald damselflies. Other invertebrates show a similar pattern, with the northward spread of the bee-wolf, the arrival of the tree bumble-bee and plantbugs like Closterotomus trivialis from mainland Europe, and less obviously, previously garden-loving molluscs such as Spanish and Balkan three-band slugs colonising ‘wild’ habitats. And of course, it’s not just invertebrates - birds such as little egret, spoonbills and purple herons are now regular breeders, and it may not be long before glossy ibis and penduline tit become established.

We have over 40 years of convincing research and regular observation of climate change impacts, yet people are still surprised by it, and politicians are reluctant to act. The United Nations conference on climate change in Paris last month reached a global agreement to try and keep temperature rises below 2°C. In 2016 and in future, let's assure that those good intentions are turned into action by the UK government as well as the 186 other countries who signed the Paris agreement.


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