Guest blog from Ellie Crane, RSPB Agriculture Policy Officer
Arable farming is arguably one of the economic sectors most sensitive to climate change. It is also a very versatile sector: farmers have always had to respond to change. Modern farming looks quite different from early agriculture, but one thing has remained constant: plants need water, sunlight and CO2 (plus various nutrients) to grow.
Levels of CO2 in the atmosphere continue to rise – last month they reached a symbolic landmark of 400 parts per million. All else being equal, you would expect higher CO2 levels to benefit plants, including crops. Indeed some claim that higher CO2 can only be a good thing. The Wall Street Journal on 8th May published a provocative article ‘In Defense of Carbon Dioxide’ in which the authors claim that “increased carbon dioxide in the atmosphere will benefit the increasing population on the planet by increasing agricultural productivity”.
Anyone familiar with the realities of farming (and climate science!) will realise that this is a gross oversimplification. Higher CO2 may increase rates of photosynthesis, but we cannot ignore the profound changes in climate and weather patterns that go along with it.
In the UK we are luckier than many other parts of the world: arable farming should remain possible at least in some areas. Even here, though, the picture is mixed. The UK Climate Change Risk Assessment summarised the impacts of climate change on agriculture to 2100 as follows: “Warmer temperatures and higher concentrations of CO2 in the atmosphere would lead to higher yields of many crops currently grown in the UK. These benefits will not happen, however, if rising temperatures and lower summer rainfall result in increased heat stress to crops and significant decreases in soil moisture.”
Crops don’t just need water, they need the right amount of water at the right time (as well as the right temperatures and enough sunlight). Rain at the wrong time can mean that crops don’t germinate or grow properly, that farmers can’t get heavy machinery onto fields to carry out vital farming operations, or that pests like slugs suddenly proliferate. This was starkly illustrated last year. 2012 started with worries over low water tables and ended as the second wettest year on record for the UK. The National Farmers’ Union harvest survey found that wheat yields for 2012 were down 14% compared to the five year average, although there was large variation across the country. We can expect more of this ‘climate weirding’ as CO2 levels continue to rise.
Adaptation in the farming sector is going to be about decisions made by individual farmers: which crops and varieties to grow, how to manage them, whether to invest in items like on-farm reservoirs and new machinery, whether to diversify to spread the risk and take advantage of new opportunities. The farming industry is well-placed to adapt as an economic sector.
But farming provides a lot more than crops and profits. Agriculture covers 75% of the UK’s land area and is home to many of our most treasured species of animals and plants. And the way farmland is managed affects not only wildlife but also how much carbon is stored or lost by soils; how likely rivers are to flood and how clean their water is; and what sort of rural landscapes we have to work and play in. So it's clear that Government policy must provide the right mix of regulation, advice and incentives to help farming businesses adapt to climate change in ways that means they continue to provide these ‘public goods’.