The Big Debate: The consequences of changing seasons

Are our seasons beginning to change? And, if so, what can this mean for our glorious British countryside?
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The Independent Online

Visitors to the Wimbledon tennis championships in the past few years may have been surprised to see that blackberries have made it onto the summer tennis menu alongside strawberries.

This is not so much an indicator that British culinary tastes are changing, as that the British seasons appear to be changing. The traditional growing season for strawberries is late spring and early summer, while blackberries do not normally show their colour until six-to-eight weeks later.

How do we know seasons are changing?

Traditionally, spring starts on 21 March with the vernal equinox ­ the point at which night and day are of equal length, and the days start lengthening towards the summer solstice. However, spring is arriving sooner, summer and autumn are staying longer and the delayed winter season is becoming milder.

This shift in the seasons was borne out by a study of more than 500 plants and animals across Europe, published last year in the journal Global Change Biology. In what is believed to be the world's largest study of seasonal events, researchers found that events associated with the start of spring, such as the flowering and leafing of plants, were now appearing six to eight days earlier than they did 30 years ago.

Britain saw an even more dramatic change, with spring events happening 10 days earlier and particular species seeing even earlier flowerings. Wild cherries, for example, are now blossoming two weeks earlier than in the 1970s.

These observations in nature are backed up by Met Office data. June 2007 was the wettest on record for many parts of the country, with up to 400 per cent more rain than normal and widespread flooding in Yorkshire and the North East. While last year was the hottest on record across the UK, with a mean temperature of 9.7°C, 1.1°C above the 1971 to 2000 long-term average.

What does it mean for the countryside?

Such marked climatic changes could see British woodlands take on a more Mediterranean look, with olive groves, vines and sunflower fields all familiar sights. Many trees which thrive in the likes of southern France will become much more common further north. These include walnut, poplar, olive, sweet chestnut, plum, kiwi fruit and Corsican pine trees.

A warmer Britain is also likely to see 'new' species of birds, moths and other insects arriving from mainland Europe. A large number of 'new' insect species have already become established in the UK, such as the horse chestnut leaf miner moth, and their rate of arrival is increasing.

Scientists expect new butterfly species to follow shortly. They might be pretty additions to the British countryside, but they will help drive out native species, such as the Scotch argus, which will become more vulnerable as temperatures continue to rise.

The list of newcomers will also include farming and forestry pests, which are certain to cause headaches for farmers already struggling to contend with droughts and flooding. Farmers will also struggle to cope with the greater unpredictability that climate change brings. Rising temperatures can affect crop yields and quality, while rising carbon dioxide concentrations and longer growing seasons can also have an impact. We know that crops have temperature thresholds at which yields and quality begin to decline, but little is known about the precise impact of long-term climatic changes of the kinds being predicted by current models.

Scientists are concerned that the earlier arrival of spring and longer autumn could upset the delicate balance between nature, plants and animals, so species become out of sync with their food sources.

A study published in the Royal Society's journal found that the migration and breeding of the great tit, puffin and red admiral, among others, are moving out of step with food supplies.

Caterpillars, for example, are the staple food of infant great tits. As the emergence of caterpillars in spring gets earlier, so the great tit needs to bring forward its egg laying. The problem is that some great tits, such as those in Wytham Wood in the UK, have brought their egg laying forward by too much, while others are laying at the same time as previously.

Is it just the UK?

Further afield, the seasons are being knocked off balance by climate change, too. In the USA, milder winters are creating problems for farmers of high-value crops such as peaches, plums, pistachios and walnuts, which need a period of cold in the winter to bloom properly. And in Alaska, beetles and other pests once kept in check by winter cold are flourishing, and fires are burning millions of acres as summers get longer and hotter.

The fear is that while nature has always had to adapt to changing climate conditions, some of the changes underway are simply too rapid for species to evolve new strategies for survival. Their options are also being narrowed by the rapid conversion of eco-systems, such as the draining of wetlands, the felling of forests and the development of coastlines.

There is also an economic impact. The high winds and storms that battered the UK in January 2007 left behind an estimated insurance bill of £1 billion. The recent floods will lead to many millions more in insurance payouts. And each time it happens, insurance gets more and more expensive. According to the Association of British Insurers, more than half a million homes are now at a high risk of flooding, up more than 100 per cent in the last five years. And with the average flood claim costing between £30,000 and £40,000, freak weather is anything but cheap.

What can we do?

One option is novel grass varieties with more extensive root networks that increase soil's capacity to hold water and thereby help to counter both summer droughts and flash flooding.

But answers are less forthcoming for the nation's fauna. Migration and processes of nature are complex, and only by obtaining a clearer picture of how they really work will researchers be able to plan strategies for mitigating the effects of global warming. Which suggests that our whole approach to conservation may have to radically change.

What is HSBC doing to help? Find out more at to change

HSBC believe the effects of a changing climate will have serious implications for the sustainability of our business and the economy at large. We consider the greatest business risk associated with climate change will be the impact it will have on our customers, including those in the countryside. We can also see considerable business opportunities for our rural customers, for example, renewable energy from wind, water and waste, and the cultivation of new crops.

The impacts of climate change are already being witnessed in the countryside; farmers in particular recognise the importance of the issue. In the UK, more than 70 per cent of land is cultivated for agriculture and HSBC will assist its rural customers in understanding the climate change-related risks and opportunities.

HSBC has a team of specialist banking managers dedicated to agriculture and farming-related businesses in the UK. They relationship manage over 7,000 of the largest farm businesses and work closely with local farming communities. HSBC Agriculture are working with this sector of the economy helping businesses adapt to climate change and develop more sustainable agricultural businesses. Indeed, we are already supporting farmers who grow alternative crop varieties and reduce the carbon footprint of their agricultural operations.

HSBC's Carbon Finance Strategy, launched in June 2006, aims to identify further opportunities to work with existing and new clients globally to promote energy and transport efficiency and lower carbon energy technologies that are commercially and technically viable, such as wind power, solar power, biofuels, landfill gas, methane capture and geothermal energy.