A small but purposeful signal of EPA’s renewed power to address to the growing climate crisis is apparent in the agency’s release of its Climate Change Indicators in the United States The resource is designed to present the compelling and clear evidence of changes to our climate reflected in record-high temperatures, snow and rainfall patterns shifting, river flooding, droughts, heat waves and wildfires, among other factors.
The agency, which says it is restoring the role of science in addressing the climate crisis, reports that many of the observed changes listed in the indicators are linked to the rising levels of carbon dioxide and other greenhouse gases in our atmosphere, attributable to human activities.
EPA partnered with more than 50 data contributors from various government agencies, academic institutions, and other organizations to compile the key set of indicators related to the causes and effects of climate change. The indicators, each of which were peer-reviewed by experts, also provide important input to the National Climate Assessment (NCA), a quadrennial report mandated by Congress in 1990 directing 13 federal agencies and departments, including the USDA, the EPA and the Departments of Interior and Energy, to conduct or use research on global change and its impacts on society.
While the next national assessment is due in 2023, the fourth NCA issued in 2019 warned that major U.S. crop yields are expected to decline because of increases in temperatures and possible changes in water availability, increased soil erosion, and more disease and pest outbreaks. The climate change indicators released last week tend to support some of the dire predictions laid out in that assessment two years ago, predicting reduced food and forage production, an increase in wildfire intensity, accelerated depletion of water supplies for irrigation, and an expansion of the distribution and incidence of pests and diseases among crops and livestock.
Some specific findings laid out by the indicators include the fact that 2016 was the warmest year on record, 2020 was the second warmest, and 2010-2020 was the warmest decade on record since 1880, when thermometer-based observations began. Also heat waves are occurring more often across the United States, their frequency having increased steadily. The contiguous 48 states have gone from averaging of two heat waves per year during the 1960s to six per year during the 2010s.
Indicators also showed that the average length of the growing season in the contiguous 48 states has increased by more than two weeks since the beginning of the 20th century.
But the scientists and researchers who put together the indicators also suggest that changes in the length of the growing season can have both positive and negative effects on the yield and prices of particular crops. Overall, warming is expected to have negative effects on yields of major crops, but crops in some individual locations may benefit.
A longer growing season could allow farmers to diversify crops or have multiple harvests from the same plot. However, it could also limit the types of crops grown, encourage invasive species or weed growth, or increase demand for irrigation. A longer growing season could also disrupt the function and structure of a region’s ecosystems and could, for example, alter the range and types of animal species in the area.
The indicators show that sea level rose along much of the U.S. coastline between 1960 and 2020, particularly the Mid-Atlantic coast and parts of the Gulf Coast, where some stations registered increases of more than eight inches. Evidence of how these trends are affecting agriculture can be found in research underway in Maryland where saltwater intrusion is reducing agricultural crop yields and creating salt-stressed soils. This study – performed by University of Maryland scientist Dr. Kate Tully and partially funded by the Harry R. Hughes Center for Agro-Ecology – looks into ways intrusion brought on by sea-level rise and climate change can be mitigated.
The new EPA combined indicators site, which was left virtually dormant for the past four years, has been upgraded from earlier incarnations, offering an enhanced user experience with interactive tools – graphs, maps, and figures – that boost the importance of markers showing how climate change can affect human health and the environment.
The EPA says more content will be posted on the site as it pursues its mission of protecting human health and the environment by tracking and reporting greenhouse gas emissions, leveraging sound science, and working to reduce emissions to combat climate change. SfL lauds the agency for making this information widely available and urges our agricultural partners and stakeholders to access it to adopt climate smart agriculture systems and practices that can sustainably intensify production, improve resilience and reduce and/or sequester greenhouse gases.