West Midlands

The majority of the West Midlands is made up of arable and horticultural land (34.6%; in England: 35.1%) and improved grassland (35.4%; in England: 31.1%). Other major land uses are for broadleaved, mixed and yew woodland (8.3%; in England: 6.8%) and built up areas and gardens (8.7%; in England: 7.1%). Overall, the majority of agricultural land in the West Midlands is used for permanent grazing (39.9%) and arable crops (37.4%). Of these crops, by far the most extensively grown is wheat, although field beans, oilseed rape and winter and spring barley are also significant (2).

Agriculture is historically, and continues to be, one of the most important sectors in the West Midlands, not only in land use terms, but also through its contribution to society and the environment. The gross value added by agriculture, hunting, forestry and fishing is higher than the UK average, but is still relatively small at 1.5% (2).

East of England

Agriculture is an important activity in the East of England in terms of land use and economic activity. Primary agriculture contributes 2.1% to GDP in the East of England (3).

Wales

In 1997 Agriculture, Forestry and Fishing accounted for less than 2% of the Welsh economy. Its rate of growth has been slower than that of the rest of the economy for the past 20 years and was actually shrinking between 1985 and 1995(4).

South West

The South West region has the second largest agricultural workforce and proportion of agricultural employment in the country, and the third highest share of agricultural output in regional GDP. Agriculture thus directly sustains 3.7% of the regional workforce, generating 2.2% of regional GDP (5).

Scotland

Nearly four fifths of the total land area of Scotland is used for some form of agriculture, of which the vast majority is rough grazing. The agriculture workforce was about 2.5% of total Scottish employment in 1997 and about 8% of the rural workforce (6).

The effects of climate change on agriculture are now broadly understood. These include an extended growing season, the potential for new crops, an increased requirement for water for summer irrigation, a potential loss of competitive advantage compared with other locations, and reduced die-off of pests and diseases due to warmer winters. Some of these changes are already occurring but within the farming community generally there is not much awareness or concern. At present there are more pressing issues on the agricultural agenda, including BSE, the aftermath of Foot and Mouth disease, the implications of the Curry Report and changes to the Common Agricultural Policy (5).

England

In September 2008, 60% of farmers surveyed in England said they were already affected by climate change and more than half expect to be affected in the next ten years (7).

Scotland

Agriculture in Scotland is dominated by subsidy payments, which insulate the farmers from some detrimental climate impacts (6). Climate change in Scotland needs to be larger than projected over the next century for it to become the major driver in modifying agriculture (6). Individual components of agricultural systems appeared inherently robust and adaptable. Nevertheless, economic and social factors remain by far the most important driver on the sector.

Wales

The impact of climate change on agriculture in Wales may be felt at three levels (8):

• there may be biological impacts on individual plants and animals;
• it may be necessary for farmers to alter the management of their farm in some way;
• there may be impacts through the global market place on the range of agricultural enterprises which would be profitable in Wales (market induced changes).

Climate change can have an impact on the growth and well-being of crops and animals in several ways. These may include increased maximum and minimum temperatures, impacts of drought (in the summer) and water logging (in the winter), impacts of storms, elevated ambient levels of CO2 and increased ultra violet radiation (4).

Saturated soils

Saturated soil cannot support the weight of tractors and implements as well as drier soil, so that machinery can become stuck in ruts or soil becomes more compacted by the weight, reducing its ability to grow crops (3). There can be an increased growth of weeds while the land is too wet to deal with them (5).

Seeds in flooded land are prone to rotting, and plants can drown if the ground is waterlogged and air cannot get to the roots(2,5). Water logging will limit the release of nitrogen from the soil, restricting the nutrients available for plant growth(2). Reduction in water quality due to leaching of nutrients, fertilisers, pesticides etc. (5).

Floods and erosion

Some agricultural land is likely to be lost due to fluvial and coastal flooding; the extent of which would depend on the climate change scenario and extent of flood risk. Increased flood risk may lead to changes in land use as farmers abandon arable cropping on such land(3,5). Flash flooding increases the risk of slurry pollution events (5).

Damage will increase due to run-off – soil erosion, blockage of drains, damage to rural road network/field access. Standing crops will be damaged more often by heavy precipitation, high winds, flash floods etc. In fact, some crops currently grown on light soils (e.g. potatoes) may become inappropriate due to unpredictable weather events such as intense storms (5).

The aggregate UK estimate for agricultural damages arising from the October/November 2000 floods, a 1-in-50 year event, was £90 million based solely on potatoes and wheat (9). These data only refer to crops; impacts on livestock were not identified, and therefore the estimates presented have to be seen as representing the lower bound. The impacts on crops were:

• Potato crops - 30% unharvested nationally;
• Sugar beet damage resulting from crops rotting in the ground;
• Cereals - up to 50% of the crop not planted;
• Dairy - impacts on milk collection and forage stocks;
• Livestock - poor lambing, damage to fencing and high straw prices;
• Horticulture - 25% increase in costs of harvesting vegetables.

In terms of the response to flooding, as flood frequency increases so agricultural land use is expected to change towards less intensive activities (10). Observations of farmers’ behaviour suggest that there are specific thresholds of flooding frequency at which different types of farming activity are abandoned. Some commonly accepted minimum intervals between flood events, related to various crops, are (10):

Acceptable minimum intervals between floods (in years) Crop Whole year April - October Horticulture 20 100 Arable and roots 10 25 Arable cereals 5 10 Intensive grass 2 5 Extensive grass <1 3

UK

Warm weather hastens crop development and brings earlier harvests. However in cereals, the reduced duration of the growth period tends to reduce yields. Similarly a shortage of water tends to slow growth development and reduce yield. However in the field, warm weather causes earlier flowering than usual and this causes yield formation to occur earlier in the summer, which is normally before soil moisture reserves have been exhausted. So historically in the UK hot dry summers have been associated with higher than average yields (8).

However, the exact impact on yields depends crucially on the timing of the drought relative to the development of the crop, and this may vary from year to year and from location to location (8,28).

A reduction in rain over the summer months is likely to have a number of impacts on agriculture. These relate not only to the overall quantity of rainfall, but also the increasing erratic nature of rainfall.

The1995 drought reduced yields of salad and horticultural crops (especially peas, carrots, onions, potatoes, salad onions and leeks) and fruit (on shallow soils) but cereals benefited. Protected salad crops did benefit, albeit at higher costs for carbon dioxide fertilisation due to the required additional ventilation. Overall costs to agriculture nationally from the 1995 drought have been estimated at £280 million (11).

Grass has one of the highest water demands of any crop, and lush grass relies on a relatively even rainfall throughout the year. If rainfall reduces, it is likely that quality of the grassland will be poorer. This might in turn require livestock feed to be supplemented to compensate for this reduction (2).

The drier summers, without rain to swell the grain in cereal crops and vegetables and fruit with summer growing seasons, are likely to reduce yields from these crops. Although this will be in part counteracted by a reduction in crops lost in the field because of high or intense rainfall, it is unlikely that this will compensate completely (2). It is particularly important to have enough water available at crucial points in crop development (5). Increased depth of roots due to dry conditions put the nutrients out of reach for some crops (5).

Maize may replace some wheat but needs irrigating to avoid drought. Coarser soils are an important limiting factor during periods of drought for short term vegetables, such as lettuce, with roots less than 0.3 m. Whilst irrigation may be profitable for high value crops it is not for cereals or sugar beet. There is currently no consensus about whether plants will use water more efficiently under higher CO2 conditions (11).

Thames region

Reduced summer soil moisture will be a key constraint.The pressures which agriculture puts on water supplies is already felt in the Anglian region, which is the driest in the UK. Similarly the Thames region is facing great pressures.Irrigation demand for key irrigated crops could increase by between 12 and 27% in the next 25 years according to Environment Agency research (the scenarios used to make these predictions is not evident) (3).

Wales

The need to irrigate in Wales will be far less than in parts of England, but even so on-farm water storage may be advantageous in some areas. However, the exact economics of irrigation depend critically upon prevailing market and legislative conditions (8).

East Anglia and North West England

Holman et al. (12) studied changes in future agriculturein East Anglia and North West England. Changes in future agriculture differ between the two regions. In East Anglia, arable agriculture is quite stable under all futures, although the area of grassland is dramatically reduced in the 2050s High scenarios due to the lower yields in the drier summers. However, increasing irrigation demand will be increasingly hard to satisfy, particularly in the 2050s, under many of the socioeconomic scenarios. In the North West there is a very much greater range of outcomes, though all future scenarios suggest a reduction in grassland with the greatest in the 2050s High climate scenario combined with the Regional Stewardship socio-economic scenario.

Livestock - heat stress

There is a risk of over-heating of livestock (11). Livestock production systems could be affected by higher temperatures, leading to increased requirements for drinking water, water wallowing sites for pigs and water to cool livestock units (3,5).

Livestock - Bluetongue disease

Bluetongue disease outbreaks have occurred in northern Europe since August 2006. The disease mainly affects sheep. The virus responsible for the disease formerly occurred in South Africa. It has been able to spread in Europe because it is also transmitted by endemic biting midges. The spread of bluetongue virus in sheep across Europe has been partly attributed to climate change: midge population size, mortality rate and biting rate are temperature-dependent, as is the virus replication rate, which governs the time taken for an infected vector to become infectious (30).

In 2007, a large outbreak affected England and Wales. For these areas, future Bluetongue disease riskhas been assessed by simulating outbreaks under future climatic conditions (29). Two scenarios of climate change were used: a moderate and high-end scenario (the so-called RCP 4.5 and 8.5 scenarios). The results show that by 2100, bluetongue risk extends further north, the transmission season lengthens by up to three months and outbreaks are larger on average.

Future Bluetongue outbreaks in England and Wales may be double the current size by the 2050s. By the 2080s, outbreaks may be slightly higher than double the current size for the moderate scenario of climate change, while a more dramatic increase is projected for the high-end scenario. Under the latter scenario, a1 in 20-year outbreak at present-day temperatures becomes typical by the 2070s (29).

There is a silver lining, however. Animal movement restrictions are sufficient to prevent truly devastating outbreaks. Without these restrictions, a future unlikely ‘worst-case scenario’ could have an outbreak size of more than 61,400 farms (53% of all farms) in high-farm-density areas of England and Wales. With movement restrictions in place, this number would be ‘only’ 3,000 farms. Thus, efficient detection and control measures to limit the spread of vector-borne diseases will be increasingly vital in future, warmer climates (29).

Cereal

If winter temperatures rise, a change in cereal varieties may be required. Winter cereals differ in their vernilization (the number of days of cold weather that a plant needs to go into its sexual stage and produce seed). While some will be more suitable to milder climates, others will not be suitable for growing, since the lack of freezing days will lead them to be simply vegetative, without producing grain. Although spring cereals will not be affected, it will be necessary to consider the warmer winter temperatures when considering winter cereal variety choices. One view is that genetic modification may offer scope to develop more cereals that do not suffer as a result of mild winters (11).

One study of the impacts of climate change found that the amount of available land well suited for winter wheat declines with a rise in temperature and constant, or a 10% increase in, precipitation. Much of the moderately suited land becomes more marginal.Maize may replace some wheat but needs irrigating to avoid drought (11).

Fruit

Many fruit trees and bushes also require cold winter weather to move from dormancy to flowering and growth. As with winter cereals, these crops, which include blackcurrant, apple and raspberry, require an accumulation of temperature below a particular threshold in order to form flower buds. Therefore, an increase in winter temperatures could delay formation of flower buds, or result in abnormality or failure of flowering, which would thereby reduce the subsequent crop of fruit (2).

Diseases and pests

For arable farming, milder winters and warmer summers carry the risk of more diseases and pests. This will be exacerbated by increased wet weather in the winter. Some of these pests and diseases are already present, but are controlled by the cold weather in the winter, while others may develop or move from more southern areas (5).

It has been concluded (13) that the yield of winter wheat in England and Wales probably will not suffer from climate change by the 2050s with respect to the baseline 1960–1990. The effect of changing climate was assessed on maximum soil moisture deficit, drought-related reduction of potential yield and wheat yields by using a crop simulation model, climate scenarios and a stochastic weather generator:

• Maximum soil moisture deficit is likely to increase in the future, especially on shallow soils, and the potential winter wheat yield will more likely suffer from droughts by the 2050s.
• However, average wheat yields are likely to increase by 1.2 to 2 t/ha (15–23%) by the 2050s because of a CO2-related increase in radiation use efficiency (RUE).

According to their results (13), changes in the variance of weather variables will have little effect on grain yields. Ignoring genetic improvement in varieties, yields are predicted to increase more until the 2020s than in the following 30 years. A sensitivity analysis for crop growth parameters suggests that further yield gains (1 t/ha) are possible with new varieties that increase the grain filling period.

A blank cell indicates that no specific issues were identified for the region besides those noted in the first row. Each region identified and discussed issues differently, so this table might not provide comprehensive coverage of all issues.

Region Expected positive impact on agriculture and horticulture Expected negative impact on agriculture and horticulture Uncertain impact on agriculture and horticulture Majority of regions Potential to grow new crops. Longer growing season. Enhanced yields More, or different, pests and diseases. Increasef need for irrigation. Damage to crops and soils from intense winter rainfall; difficulty accessing fields. Reduced yields if no irrigation   South West   Potential loss of competitive advantage   South East     Higher drought risk may call for more on-farm water storare reservoirs London       East of England   Increased soil erosion. Land in floodplain flooded more often Change in timing of planting, harvesting, fertilizer application and ploughing techniques East Midlands   Difficulty predicting suitability for planting in Autumn. Heat stress upon livestock. Loss of agricultural land from sea level rise   West Midlands Reduced problems for livestock freezing in winter Land use limited by higher flood risk. Fruit, vegetable and cereal yields to decline without irrigation Changes to timing of formation of flower buds on some crops Wales   Decreased yield. Heat stress for animals   North West   Increased soil erosion. Increased heat stress on animals   Yorkshire & Humber Increase in growing season along Yorkshire/Lincolnshire coasts Loss of land and property from landlides. Increased demand for salad crops   North East Growing season could extend by 30-100 days by 2080s. Arable farming becomes viable in some areas Soil erosion may increase New methods of livestock and crop management Scotland   Increased water demand, particularly in East   Northern Ireland More mixed agriculture with spring-sown cereals making a comeback in East of region Farming in West may become more economically marginal  

Increased temperatures and carbon dioxide levels and a longer growing season could benefit certain agricultural and horticultural crops and trees. This could benefit agriculture but potential opportunities are closely linked to consumer demand (2,11). However, increased summer drought may offset the benefits through reduced growth of crops and forages (5). Decreasing soil moisture and availability of water supply for irrigation may constrain opportunities to capitalise on warmer temperatures (3).

The drier summers might also offer an opportunity for the agriculture sector by allowing new types of crops to be grown. This might affect the horticulture sector through increased opportunities for growing soft fruits, and also for agriculture where it might be possible to grow sunflowers and soya (2,11,26), and grapevine and bio-fuels including vegetable oils (5). This could also link to changes in consumer demand if warmer weather increased demand for salads and fruit (5). Some crops will become increasingly commercially attractive e.g. sugar beet and potato (3).

For the East of England, however, research has shown that potential for new crops would be very limited as yields would remain too low under all (UKCIP98) scenarios at least until the 2050s (3).

For the United Kingdom, the change of crop yield in 2080 referred to 1990 has been estimated based on several combinations of models and scenarios; the outcomes show an increase ranging from 1.5% - 20.0% (18). Studies indicate that there are significant regional differences, though. Projected crop yield change (winter wheat, spring wheat, rice, grassland, maize and soybeans) for the UK is spatially heterogeneous across all emissions scenarios; e.g. the north of the UK is generally associated with yield increases with climate change, whereas the south is associated with yield decreases (27).

Wheat production

The future UK climate is expected to remain favourable for wheat production by the mid-21st century, according to multi-model projections for a moderate (RCP4.5) and high-end scenario of climate change (RCP8.5). According to these projections, hotter and drier summers would improve sowing and harvesting conditions and reduce the risk of lodging. The probability of late frosts and heat stress during reproductive and grain filling periods would likely remain small in 2050. Wetter winter and spring could cause issues with waterlogging. The severity of drought stress during reproduction would generally be lower in 2050. Prolonged water stress does not increase considerably in the UK, as may be expected in other parts of Europe (32).

For the developed nations under all climate projections an expansion of potential land suitable for crop cultivation in 2080 with respect to 1990 was predicted, mainly in North America (40% increase over the 360 million hectares under current baseline climate); northern Europe (16% increase over current 45 million hectares); Russian Federation (64% increase over 245 million hectares) and in East Asia (10% increase over 150 million hectares) (25).

Model results indicated that agriculture in developed countries as a group would benefit under climate change. Agricultural GDP mostly increases in the Former Soviet Union (up to 23% in scenario A2); while only Western Europe loses agricultural GDP, across all GCM scenarios. Model results indicated decreases in agricultural GDP in most developing regions, with the exception of Latin America (25).

According to these scenarios the developing countries will become more dependent on net cereal imports. Climate change will add to this dependence, increasing net cereal imports of developing regions by 10–40% across GCM climate projections (25).

From research it was concluded that socio-economic assumptions have a much greater effect on the scenario results of future changes in agricultural production and land use then the climate scenarios (19).

The European population is expected to decline by about 8% over the period from 2000 to 2030 (20).

Scenarios on future changes in agriculture largely depend on assumptions about technological development for future agricultural land use in Europe (19). It has been estimated that changes in the productivity of food crops in Europe over the period 1961–1990 were strongest related to technology development and that effects of climate change were relatively small. For the period till 2080 an increase in crop productivity for Europe has been estimated between 25% and 163%, of which between 20% and 143% is due to technological development and 5-20% is due to climate change and CO2 fertilisation. The contribution of climate change just by itself is approximately a minor 1% (21).

Care should be taken, however, in drawing firm conclusions from the apparent lack of sensitivity of agricultural land use to climate change. At the regional scale there are winners and losers (in terms of yield changes), but these tend to cancel each other out when aggregated to the whole of Europe (19).

Future changes in land use

If technology continues to progress at current rates then the area of agricultural land would need to decline substantially. Such declines will not occur if there is a correspondingly large increase in the demand for agricultural goods, or if political decisions are taken either to reduce crop productivity through policies that encourage extensification or to accept widespread overproduction (19).

Cropland and grassland areas (for the production of food and fibre) may decline by as much as 50% of current areas for some scenarios. Such declines in production areas would result in large parts of Europe becoming surplus to the requirement of food and fibre production (19). Over the shorter term (up to 2030) changes in agricultural land area may be small (22).

Although it is difficult to anticipate how this land would be used in the future, it seems that continued urban expansion, recreational areas (such as for horse riding) and forest land use would all be likely to take up at least some of the surplus. Furthermore, whilst the substitution of food production by energy production was considered in these scenarios, surplus land would provide further opportunities for the cultivation of bioenergy crops (19).

Europe is a major producer of biodiesel, accounting for 90% of the total production worldwide (23). In the Biofuels Progress Report (24), it is estimated that in 2020, the total area of arable land required for biofuel production will be between 7.6 million and 18.3 million hectares, equivalent to approximately 8% and 19% respectively of total arable land in 2005.

The agricultural area of Europe has already diminished by about 13% in the 40 years since 1960 (19).

Possible adaptation measures are (3)

• changes in land use,
• adoption of better adapted crop varieties and animal breeds;
• adoption of techniques to control soil erosion;
• close crop monitoring;
• development of weed, pest and disease control strategies;
• adoption and development of appropriate low-cost water conservation and water-efficient irrigation methods.

Many fruit trees and bushes require cold winter weather to move from dormancy to flowering and growth. An increase in winter temperatures could delay formation of flower buds, or result in abnormality or failure of flowering, which would thereby reduce the subsequent crop of fruit. In the short term, adaptation could involve substitution of cultivars to those that require less cold weather, while it may be possible to move away from crops such as apples to those such as peaches in the long term (2).

Horticulture is not so vulnerable to external conditions and will probably benefit in terms of reduced heating bills from an increase in winter temperatures. There may be a potential problem arising from restrictions on water availability in the future, however. Water demand would go up with higher external temperatures and there may be a need to top-up rainwater which is collected from glasshouses with tap water. A possible response would be to develop more winter water storage facilities (11). On-farm storage of excess winter precipitation may be the answer, but this will require financial outlay and man-hours in terms of reservoir construction (5).

It may be wise to change land use in view of sustainable farming under climate change (11). At the national scale, agriculture represents only 1-2% of total water demand, but at the local level it can be much higher - and with demand often highest when supplies are most depleted. 58% of the East Midlands area, for instance, is closed to further summer abstraction (15). In some areas the vulnerability of groundwater supplies is described as ‘very high’.

Use of irrigation water is necessary in much horticulture because the supermarket chains expect uniformity in the produce that goes onto shelves. Potatoes, for example, often develop scars if they do not receive water at exactly the right times. Hence, to produce the 'perfect' potato requires irrigation. Likewise, food processors such as crisps manufacturers will specify a potato without scars (11).

The problem of water abstraction due to climate change is difficult to specify in detail because of scientific uncertainty in the future distribution of rainfall. Certainly, more winter storage of water will be required in some areas since restrictions on irrigation are likely to exceed the licenced volume of irrigation water. There may be a need for grant aid support to help farmers develop winter water storage reservoirs (11).

It is stated that farmers will be successful in adapting to the climate change scenarios that are projected for 2050 provided adequate water resources are available (10). For East Anglia and North West England an increase in the productivity of crops is expected, especially sugar beet and potatoes (but associated with a greater need for irrigation) and specialisation in cereals and root crops arising from economic change. In these regions there will be a change from grassland to arable (5% arable land use becomes 17%) arising from the reduced competitiveness of dairy farming due to the economic scenario, but also due to the increased availability of arable options arising from climate change. Even in the uplands, the arable area may increase from 8% to 18% (10). The impact of climate change on agriculture, however, strongly depends on the chosen climate change scenario (10).

At the global level simulation results indicate only small percentage changes from the baseline reference case with respect to cereal-production. It is suggested that two levels of adaptation considered in the simulations, i.e. autonomous adaptation at the field level, such as changing of crop calendars and cropping systems as a function of climate; and market adjustments at both regional (re-distribution of capital, labour and land) and global (trade) levels, can successfully combine to reduce otherwise larger negative impacts (25).

Additional climate change pressures may arise, however, by changes in the frequency of extreme precipitation events such as floods and droughts, which may diminish the capacity of countries to adapt, especially in poor tropical regions (25).