Climate Change Information Highlights
Frequently Asked Questions and Discussed Topics
- What is the difference between weather and climate?
- What is climate change?
- What is the difference between climate change and climate variability?
- The greenhouse effect and climate change
- NRCS Conservation Practices and Climate Change
- Climate change impacts on agricultural production
What is the Difference between Weather and Climate?
Weather consists of the hourly and day-to-day variations in the meteorological conditions, such as rain, snow, solar radiation, wind, or temperature in a local area. Climate is the average weather conditions in a given region over longer periods of time (decades or longer). A common "climatic normal" is the period of 30 years ending on a decade, e.g., 1981-2010. Other statistical measures of climate exist, such as variability between years and grouping of trends (similar conditions) among successive years. Climate can be examined on a local extent or across a broad geographic area. Measuring climatic conditions is important for agriculture. The NRCS National Water and Climate Center has a program that has a long-term collection and observation of temperature, precipitation, soil moisture, and other parameters in its Soil Climate Analysis Network (SCAN) at selected sites across the US; and of snow depth measurements at their Snowpack telemetry (SNOTEL) stations. These data are critical to predict water availability for irrigation and time of drought onset, and used weekly in the US Drought Monitor. These data are also important for issues such as flood risk for both urban and agricultural areas along river systems.
What is Climate Change?
Climate change refers to any long-term, significant shift in the average climatic conditions that a given region experiences, including temperature, precipitation and wind patterns. In addition, impacts of climate change can be expressed as changes in frequency and intensity of extreme weather conditions, for example, increase in storms with heavy rainfall, or periods of drought. Climate change is caused by both natural variations in global conditions and man-made alterations in greenhouse gas concentrations. Natural occurrences that cause shifts in the earth’s climate include changes of the earth’s orbit, solar output (radiation), or atmospheric turbidity caused by volcanic eruptions. Anthropogenic changes in global climatic conditions have occurred since the advent of the industrial revolution, caused principally by increasing atmospheric CO2 concentrations from burning fossil fuels, deforestation and other sources. Measurements show that the earth’s CO2 concentration has increased over 40% in the past 200 years, and has been recently predicted that it will remain above 400 ppm in the future (Betts et al., 2016, Nature Climate Change). For the latest measurements of important signals of conditions, see NASA Vital Signs of the Planet. Impacts of climate change directly linked to fossil fuel burning (and other human activities) involves changes in global temperature, frequency of extreme weather, sea level rise, and loss of glaciers in the Artic and Antarctica. Extended periods of drought are also linked to climate change. Climate Smart Agriculture is an internationally supported concept that stresses (1) sustainably maintaining or increasing agricultural productivity, (2) increasing adaptation and building resilience to farms to minimize the impacts of climate change, and (3) reducing agricultural greenhouse gas emissions. NRCS provides financial and technical assistance for a wide range of conservation practices to assists farmers and ranchers in these three areas.
What is the Difference between Climate Change and Climate Variability?
Climate change involves significant changes in the climate system over time periods ranging from decades to centuries. Climate variability refers to inherent fluctuations within the climate system. These fluctuations can occur on a variety of timescales, from seasonal and annual, to longer-term fluctuations, like the “Little Ice Age” of the 15th through the 18th centuries. The variability in climate may result from alteration in solar radiation or volcanic activity. Seasonal fluctuations can result from the El Niño-Southern Oscillation (ENSO); the El Niño - La Niña phenomena, two opposite phases of a climatic pattern. El Niño is characterized by unusually warm ocean water temperatures in the eastern equatorial Pacific Ocean, while La Niña brings unusually cool ocean water temperatures into this region. These patterns of oceanic waters result in changes in the global atmospheric circulation pattern, thus impacting rainfall and temperature trends across sections of the U.S. and other parts of the world. For example, the El Niño generally results in heavy rainfall on the west coast, increased rainfall from Texas to Florida, and mild winters in the northern latitudes of the U.S. Impacts are also possible in other continents, for examples, El Niño has been found to increase chances of drought in countries such as Australia, India, and parts of Africa.
The Greenhouse Effect and Climate Change
Greenhouse gases (GHGs), such as carbon dioxide (CO2), methane (CH4), nitrous oxide (N2O), and water vapor (H2O), are a critical part of our climate system. These gases trap heat at the earth’s surface, warming the planet. Without these gases, most of the currently cultivated regions of the earth would be too cold for agricultural production. However, human activity is contributing to increases in GHG concentrations in the atmosphere and these increases are causing potentially detrimental changes in temperature and other aspects of climate. According to the EPA GHG Inventory, agricultural sources accounted for 8.4 percent of the total GHG emissions in the US in 2014, largely arising from agricultural soil management (nitrogen fertilization), enteric fermentation, manure management, and rice production. Gases (principally N2O and CH4) from these sources can be reduced by altering conservation practices with minimal economic impact in terms of net profits. To understand more about greenhouse gases and on-the-farm methods to reduce them, you are encouraged to take the NRCS climate change courses on AgLearn (for employees) or at eXtension.
NRCS Conservation Practices and Climate Change
Farmers, ranchers, and forest landowners are witnessing increasing vulnerability to their operations from variations in temperature and precipitation and from climate-related events such as fires, invasive pests, droughts, and floods. NRCS help farmers and ranchers understand the vulnerabilities of cropping systems that changing climatic conditions present. Our goal is to provide financial and technical assistance to improve conservation of natural resources. Thus, the agency focuses on information delivery and assistance to producers and landowners to increase conservation practices on private lands that build resilience to variable climatic conditions and extreme weather. The backbone of NRCS data for designing assistance is the National Cooperative Soil Survey Program. The soil survey, though the Web Soil Survey, provides information on soil and ecological site resources of farms and ranches across the U.S. Also, there are a wide range of NRCS Programs and initiatives that address different resource concerns. Two major programs for conservation are the Conservation Stewardship Program and the Environmental Quality Assessment Program (EQIP). The EQIP program provides technical and financial assistance to producers to add conservation practices to farms and ranches. These practices can address a range of issues. For example, the NRCS Soil Health Initiative is designed to demonstrate different cropping practices and conservation measures to producers that can be used together as a soil health management system to increase carbon and build more resilient landscapes. Practices such as cover crops and reduced/no tillage increase the carbon content of soils, increase water and nutrient retention, water infiltration, rooting depth, microbial activity, and decrease erosion. Nutrient management practices of for cropping systems, especially involving the use of nitrogen, have been proven very effective if producers follow the 4 R’s. Also, reduced tillage and other conservation practices can be used to increase energy efficiency on farms, an important measure to reduce GHG production. Also, proper management of manure can reduce the production of methane and carbon sequestration can be increased by agroforestry practices. These actions and others are the basis for the USDA Building Blocks for Climate Smart Agriculture and Forestry. In support of the Building Blocks, NRCS created a special EQIP initiative of $72 million in 2016 to invest in conservation practices that support the sequestration of carbon and mitigation of greenhouse gases.
In addition, producers have opportunities to take advantage of Environmental Markets related to ecosystem services such as carbon. An ecosystem service that can be measured and quantified when adding conservation practices to lands may become part of an environmental market, potentially increasing farm income.
Climate Change Impacts on Agricultural Production
Climate change and climate variability present a challenge to ecologically, economically, and socially sustainable land management. Drought, floods, and temperature fluctuations due to climate change can directly affect agricultural operations through damage to crops and livestock. Indirect effects of climate change include higher soil erosion rates, more invasive species of plants and insects, and changes in soil and vegetative relationships. Climate change has significant regional differences, and the consequences of these changes are variable. Therefore, regionally and locally unique solutions for adapting to these changes must be developed. The USDA Climate Hubs have written vulnerability assessments of each U.S. region that outlines the climate change risks, consequences and potential solutions.
NRCS is actively seeking new solutions to conservation issues and has continued to engage partners and others in these investigations. The Conservation Innovation Grants (CIG) program, authorized by the 2002 Farm Bill, has focused on issues related to GHG mitigation, C sequestration, environmental markets, and water quality, and other solutions to conservation problems. The CIG program awards funding for creative projects to cooperators and partners for new solutions in conservation. The Regional Conservation Partnership Program invests funding to conservation issues across the nation and seeks equal investments from partners to create conservation solutions. In 2016, NRCS funded 84 high-impact projects that cover all 50 states and target all eight designated Critical Conservation Areas.
Top Image: Photo courtesy of USDA Forest Service
Middle and Bottom Images: Photos courtesy of USDA-NRCS