The U.S. Department of Agriculture (USDA) on February 5 released “two comprehensive reports that synthesize the scientific literature on climate change effects and adaptation strategies for U.S. agriculture and forests.”
The effects of climate change will be profound and far-reaching, according to the two reports, which drew on more than 1,000 peer-reviewed studies carried out by scientists in federal service, universities, non-governmental organizations, industry, tribal lands and the private sector.
“These reports present the challenges that U.S. agriculture and forests will face in this century from global climate change,” William Hohenstein, director of the Climate Change Program Office in USDA’s Office of the Chief Economist, said in a press release. “They give us a framework for understanding the implications of climate change, in order to meet our future demands for food, feed, fiber, and fuel.”
Climate change and U.S. agriculture
Providing a comprehensive view of the anticipated effects of ongoing climate change on U.S. farms, forests, grasslands, and rural communities over the course of the 21st century, the two reports are to be incorporated in the U.S. Global Change Research Program's 2013 National Climate Assessment, a bi-annual report to the President and Congress mandated by passage of the Global Change Research Act of 1990.
Rising levels of atmospheric carbon dioxide and temperatures along with changing patterns of precipitation will affect agricultural productivity, according to Climate Change and Agriculture in the United States: Effects and Adaptation. Though the effects on the whole will be mixed, ongoing changes are in general expected to have “detrimental effects on most crops and livestock” by the middle of the century and beyond.
Crop production may shift along with changing temperature and precipitation patterns, but that doesn't lessen the likely disruption to lives, livelihoods and communities in agricultural, forest and other areas where local economies across the country depend on natural resources, or to residents of urban areas ultimately dependent on the water, food, fiber and materials ecosystems provide. For example, the annual cost of weed control in the U.S. total more than $11 billion, according to the report. That's expected to increase with rising temperatures and carbon dioxide concentrations, which will add to rising food costs.
Similarly, rising temperatures and changing precipitation patterns will also have impacts on livestock production. “Heat stress for any specific type of livestock can damage performance, production, and fertility, limiting the production of meat, milk, or eggs. Changes in forage type and nutrient content will likely influence grazing needs. Insect and disease prevalence are expected to increase under warmer and more humid conditions, diminishing animal health and productivity,” the report authors note.
Climate change, U.S. forests, adaptation and resilience
Climate change is likewise expected to have significant impacts on U.S. forests this century. According to Effects of Climate Variability and Change on Forest Ecosystems: A Comprehensive Science Synthesis for the U.S. Forest Sector, “wildfires, insect infestations, pulses of erosion and flooding, and drought-induced tree mortality are all expected to increase.” More specifically, the area burned by wildfires is expected to at least double over the next 25 years. Insect infestations are expected to affect yet more land per year than fires.
Flowing through the social-ecological system of the U.S., the direct and indirect effects “are likely to cause losses of ecosystem services in some areas, but may also improve and expand ecosystem services in others.” Areas where current infrastructure and resource production are based on historical climate and steady-state conditions, which seems likely to be the case in most, if not all, areas, are likely to be most vulnerable.
While detailing the substantial threats anticipated as a result of climate change, the two reports also highlight the need and offer recommendations for developing and enacting proactive, inclusive climate change adaptation strategies that imbue communities and ecosystems with greater resiliency.
“The ability of communities with resource-based economies to adapt to climate change is linked to their direct exposure to these changes, as well as to the social and institutional structures present in each environment. Human communities that have diverse economies and are resilient to change today will also be prepared for future climatic stresses.
“Although uncertainty exists about the magnitude and timing of climate-change effects on forest ecosystems, sufficient scientific information is available to begin taking action now. Building on practices compatible with adapting to climate change provides a good starting point for land managers who may want to begin the adaptation process.
“Establishing a foundation for managing forest ecosystems in the context of climate change as soon as possible will ensure that a broad range of options will be available for managing forest resources sustainably.”
Image credit: view_camper, courtesy flickr