We know that the planet’s thermostat is going to be cranked up at an ever increasing rate, but in March we learnt that things were going to get even hotter with news of Asda’s campaign to grow all of the ingredients needed for a good curry - here in the UK. Such news illustrates the incredible opportunities that climate change might bring to UK growers. Unfortunately, to quote the old adage, there are two sides to every story: global climate change will also threaten our existing systems of production and give rise to considerable challenges.
Before we start it would be wise to clarify a few things. Firstly, in a recent documentary on Channel 4 (The Great Global Warming Swindle, March 8) it was suggested that CO2 released into the atmosphere, as a consequence of man’s activities, had not made a significant contribution to the recent rise in global temperatures. It is important to make clear that this is a minority view and is not accepted by the vast majority of scientists involved in climate change research. Secondly, it would be prudent to clarify the terms impact, mitigation, and adaptation. These three terms are frequently misused within climate change literature, one being used in place of the other as if they were the same thing. In reality they have very different meanings: impact relates to predicting the future climate and the potential effects on people and their environment (eg will cauliflower production still be viable in Lincolnshire?); mitigation relates to reducing the production of greenhouse gases (eg develop local produce markets to reduce food miles), or enhancing their capture (eg sequester carbon in soils); finally, adaptation relates to making changes, in response to the climate, to moderate harm (eg build reservoirs) or take advantage of opportunities (eg grow new crops).
Impact and mitigation studies have been high on the agenda for Defra for a number of years now. Defra help to fund the Met Office’s Hadley Centre (who use supercomputers to predict the climate of tomorrow) and also fund the UK Climate Impacts Programme (UKCIP). The Hadley Centre and UKCIP, in conjunction with the Tyndall Centre, developed the infamous UKCIP02 climate change scenarios which inform us that the future will bring hotter, drier summers, milder but wetter winters and more extreme weather events.
In relation to climate impacts, Warwick HRI is considering how pest populations will change: which species will thrive and which will decline, will lifecycles change and will control strategies require revision? We are also increasing our understanding of the potential impact of extreme events, such as severe drought or prolonged wetness. Averages are frequently used when discussing the future climate; we are told that average annual temperatures across the UK may rise between 2C and 3.5C by the 2080s. But how useful is this information to the grower? What we really need to know is how variable weather patterns will be, in particular the extremes. A few hot days, in an otherwise average year, at just the wrong time in the crop cycle could make the difference between a good yield and total crop failure. But what are these critical times and thresholds? We are addressing these questions by simulating daily weather conditions in the future and calculating the risks to specific crops - the closest thing to a crystal ball one can have. We are also studying how climate change might affect agri-environment schemes, and how measures implemented under these schemes might be adjusted to ensure that they continue to promote biodiversity.
In relation to mitigation, we are researching ways to reduce our reliance on fossil fuels. We are assessing the practicality and cost-effectiveness of a range of technologies which may reduce energy consumption or make use of alternative energy sources. In addition, we are investigating whether we can breed oilseed rape for more energy efficient biofuel production by reducing its nitrogen fertiliser requirement. Nitrogen fertilisers consume large amounts of energy in their manufacture. Impact analysis and mitigation research will undoubtedly continue to be essential. However, it is now widely accepted that it is too late to stop manmade climate change. Consequently, there has been increased emphasis on adaptation to climate change. Ian Pearson, minister of state for climate change and environment, speaking in March at the UKCIP User Forum, said: “The choice is no longer between mitigation or adaptation; mitigation and adaptation must go hand in hand”.
But why should growers think more about adaptation than they have done in the past? After all, haven’t they always been adapting to a changing climate? Surely this is second nature to people who have always kept a keen eye on the weather? Unfortunately until recently the climate has changed relatively slowly and the pace of adaptation has equalled this rate, but we now know that the climate will change so rapidly, irrespective of how much mitigation we do, that we will have to make radical changes to our behaviour - at a global, national and individual level. Can we adapt the way we grow the crop or adapt the crop itself? Can we identify a new crop that will sustain or even increase the viability of UK horticulture? Can we change policies to promote sensible adaptation and in particular avoid maladaptation?
Defra has identified that the first logical step in the adaptation process is to make everyone aware of the challenge and they launched the ‘Tomorrow’s Climate, Today’s Challenge’ initiative which was featured in the Commercial Grower article ‘All Change’ on February 15. The second step is to rise to the challenge. One of our biggest problems is going to be water - the rain falls in shorter and heavier bursts and the summers are getting hotter and hotter, and it looks like 2007 is going to be another scorcher. Arguably, one of the most sustainable ways to address the water issue is to improve the water-use efficiency (WUE) of crops. Warwick HRI are carrying out WUE research to identify the multitude of plant genes involved in water use, which is useful for breeding drought-resistant plants, and how abscisic acid (ABA) regulates water deficit stress in plants.
Adaptation is a complex subject and depends on many variables (eg crop type, location, market conditions and the policy environment). In a unique project we are consulting with a wide range of industry experts to determine what the real climate change challenges are and how they might be addressed through adaptive activities. These adaptive activities may involve relatively quick technology transfer or knowledge transfer activities, or more complex longer-term solutions such as additional research, or policy changes.
Each of the topic areas discussed here will be developed in the following articles. Hopefully at the end of the series you will have a good grasp of the climate change research agenda at Warwick HRI and agree that UK horticulture is in a strong position to adapt to the opportunities and threats of climate change.
Website: www.go.warwick.ac.uk/climatechange
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