A recent analysis by the World Meteorological Organization concluded that uptake of climate forecasts by agricultural communities has been low due to lack of a clear understanding of their needs and insufficient interaction and communications among all involved stakeholders.California’s past history suggests that agriculture has the capacity to effectively transition to new climate regimes with economic success, but it may be only after a tortuous journey. Since 1850, California’s agriculture has been in a perpetual state of growth, transition, and adjustment . Large changes have occurred within the last 150 years in terms of acreage for California’s commodities, beginning with early mission attempts to raise livestock, grow grains, and develop horticulture; followed by the era of ruminants and then extensive wheat and barley production; then, the beginnings of intensive fruit, nut, and vegetable agriculture and large-scale beef and dairy production; ending with the present management-intensive, technologically dependent agricultural industry . During the past 40 years, the total acreage of agricultural land, including grazed land, has decreased from 37,000 to 28,000 acres,hydroponic gutter reflecting urbanization and greater intensification of existing agricultural lands. The production of horticultural crops has increased, while field crops have remained stable in acreage since the 1960s .
Lettuce, tomatoes, rice, and almonds have increased in acreage by more than 50% in the last 30 years, while two major crops of past production eras, barley and sugar beets, have declined by almost 100% during this period. Major shifts in production areas have occurred; for example, almond production in California has moved northwards over the past several decades. Within California, as the climate warms, production patterns will shift latitudinally northward, to higher elevations, or out of the state. A warmer and drier climate and expanding growing seasons could benefit olive and citrus production by extending their cultivation range northward . If crops are to decline or disappear from the Californian landscape with climate change, it is most likely to be those that use large amounts of water to produce crops of limited economic value . Many commodities in California have experienced highs and lows during the last century.Wheat production, for example, declined steadily through the 20th century due to bunt and stem rust diseases, loss of foreign markets, and competition with irrigated crops, until the 1970s when new disease-resistant varieties were introduced . For grapes, prohibition in 1919 caused a nearly total demise of the wine grape industry, which had already experienced shifts in production due to outbreaks of the invertebrate pest, phylloxera, by that time. The industry has now obviously rebounded to the point of being one of the main drivers of agricultural land use change in California.
For apricots, statewide production has decreased steadily in the past 40 years, especially since shifts, spurred by urbanization in the Santa Clara Valley, occurred due to less advantageous weather conditions in the San Joaquin Valley, but competition with foreign markets also decreased the demand for dried fruit products. Potato production historically has moved extensively around the state, experiencing fluctuations in production due to tuber-borne diseases and changes in processed vs. fresh consumption patterns. These examples show that California agriculture has the capability and agility to maintain agriculture productivity despite obstacles related to urbanization, pest and market changes for individual crops. Yet, the concern is that a changing climate may accelerate the rate at which producers must cope with specific management problems that arise, especially heat waves, water scarcity, and pests . A sequence of unfavorable years may force these land users to switch from horticultural to lower-income field crops, or to sell land for urbanization or ranchettes with affiliated small-scale agricultural enterprises. If the supply of a given commodity decreases due to climate change, and the price of that commodity increases, producers with the capacity to maintain production due to their microclimate or to technological ability may increase their profits . But, less capable producers will suffer greater losses, especially for high-input crops with large costs of production. Economic analysis of the trade offs between different production ratios of field vs. horticultural crops suggest that a shift towards more acreage of crops with lower input costs, such as field crops, compared to higher-input horticultural crops, could be advantageous in the long-run, despite lower maximum profit per acre, due to greater reliability of yield and income each year.Land use changes are driven not only by environmental factors such as climate, topography, and soil characteristics, but also by synergetic combinations of the five fundamental land use drivers . First, resource scarcity, which can lead to an increase in the pressure of production on resources, has profound implications for land use change.
It has been suggested that climate change may have either a “fertilization” effect, leading to increased yields or a “land-area” effect on crop production that would reduce arable land area and, subsequently, production . Water resources will likely be the primary environmental variable determining shifts in crop distribution since California’s water reserves are largely allocated for cropland irrigation . The loss of prime agricultural land to urbanization may also move production areas to lower quality soils, and to areas without sufficient water supplies . Second, changing opportunities and constraints, which are created by local, as well as national markets and policies, can also impact new land uses. Agriculture in California has been historically “demand-driven,” with food production goals of exporting products to the rest of the U.S. and international markets bringing huge profits to California. Depending on the cost of production and supply, either consumers or producers could gain from climate change . Climate change-induced alterations in agricultural productivity in one region can affect productivity in another region , such as the recent loss of California garlic production to China , possibly leading to collapses in one set of product markets that might trigger collapses or changes in those production systems . Third, outside policy intervention, motivated by improving or worsening agricultural conditions in different areas affected by climate change, could lead to protectionist policies seeking to improve domestic production and increase subsidies for irrigation or other inputs . Such policies can have the long-term effect of slowing economic growth, encouraging unsustainable practices, and/or increasing food insecurity. Nevertheless, incentives can potentially give rise to experimentation with new crops and products . Fourth, loss of adaptive capacity associated with increases in climate variability can greatly determine shifts in land use. Adaptation is defined by the IPCC as ‘adjustments in practices, processes or structures in response to actual or expected climatic stimuli or their effects, with an effort to reduce a system’s vulnerability and to ease its adverse impacts’. Adaptive capacity refers to a system’s increased options and capacity to reorganize after change or disturbance,hydroponic nft channel which is conferred by resilience, and is enhanced by diversification within agricultural landscapes, as well technology and access to information that increase options for successful responses . In California, for example, vegetable growers tend to minimize risks by diversifying production , while 70% of orchard producers produce only one commodity and are much more likely to rely on crop insurance as a risk-management tool . Both finding ways to produce the same crop at a profit, and relocating employment outside of agriculture, may be considered adaptation . Lastly, changes in social organization and attitudes towards climate change consequences might play a large role in determining land use shifts.
One examples is the Standard Williamson Act and the newer Farmland Security Zone , which compensate landowners for 10-20 year commitments to agricultural land use by property tax reductions . Another example is the USDA Cost-Sharing and Reserve Programs which compensate farmers for practices that increase water and air quality, wildlife habitat, or grassland conservation. Another issue is that cultural values, and even just the belief that climate change is actually taking place, strongly motivate the social response to climate and land use change . Stakeholders need to decide which risks should be retained and managed adaptively versus which risks should be shared through risk sharing contracts. Social and economic impacts of climate change must be evaluated at larger scales than site-specific studies, i.e., landscape or regional scales, to provide useful information .Agricultural land in California has gradually shifted to urban or other non-agricultural uses, driven by population growth and non-agricultural force. From 1990-2000, approximately 500,000 acres were converted from agricultural to non-agricultural uses . In one view, this trend towards less agricultural land will have minor effects on the total productivity and economic value of California agriculture. Essentially, this view builds on the high degree of past success that California has had in developing production strategies and markets for a diverse array of different types of commodities, as exemplified in Figure 8.2 by the changing geographic distribution of the top 10 counties in terms of agricultural production since 1929. A recent analysis predicts that although there will be a 10 percent net loss of farmland and irrigation water resources by 2030, this will be offset by yield growth attributable to climate change, crops with high value per acre, and growth in production per acre due to technological improvement . Climate change is assumed to increase yields of California crops by approximately 15%, based on the predictions using the simple quadratic models that were described in Section 5 . The demand for California vegetables, fruit and nuts is expected to grow, and cotton, alfalfa, and irrigated pasture acreage in the state is likely to shift to these crops. As long as relative prices and policy adjustments favor these shifts, and technological advances increase, a gradual increase is predicted in the value of food production in California, and net food exports to the rest of the world is expected to expand rather than contract. Alternatively, such successful adaptation of California agriculture to climate change might require a more cautious approach. There may be surprises in terms of weather events, for example, short-term heat waves floods, or pest outbreaks. Recent modeling has shown that California will experience longer heat waves, and more summer heat waves based on fine-scale, regional processes . In fact, extreme events may dictate outcomes from climate change more definitively than the expectation that gradual increases in mean temperatures and CO2 fertilization effects will reliably boost crop productivity. Adaptive capacity and resilience may be enhanced by taking a cautious strategy that acknowledges the need for land use changes that will assure productivity during gradual changes in climate, but also when extreme weather events, or unexpected surprises, occur. Based on the ecological literature, diversification is a key element to resilience in response to change or disturbance. Biodiversity, for example, can provide “insurance” or a buffer against environmental fluctuations . Since different species respond differently to change, more species can lead to more predictable aggregate community or ecosystem properties. Although certain species may appear to be functionally redundant for an ecosystem process at a given time, they may no longer be redundant through time. Based on this analogy, and the recognition that diversity in crops and farming systems lend economic and ecological resilience at the landscape level , it seems reasonable to adopt a diversification strategy as one element in the necessary technological advances for agriculture to cope with climate change in California. But while crop diversification can act to reduce farm business risks, there are start-up costs and problems for achieving economies of scale. Other risk-reducing strategies, such as crop insurance or the securing of off-farm income, may be readily available and preferred by producers . Another issue is the loss of wetlands, riparian corridors, and the fragmentation of farmland that is predicted to occur in California’s agricultural landscapes during the next century due to urbanization, as well as to water projects that must build levees and storage reservoirs to cope with higher stream flows . Not only do impacts on species protected by the Endangered Species Act, but impacts on other ecosystem services provided by these habitats, for example, water filtration, soil retention, or erosion regulation, need to be considered in planning land use strategies. Thus, it will be necessary to address whether adaptations to climate change by growers and institutions, will be at the expense of sustainable land use practices and extant natural ecosystems .