The Climate Crisis and Heat Stress: Maryland Farms Must Adapt to Rising Temperatures

A blog post published last month by the Chesapeake Bay Program, a collaborative partnership focused on Bay restoration, addressed the many ways that the climate crisis will affect farms in the region. Data from the program shows temperatures on Maryland’s Lower Eastern Shore, home to a high concentration of industrial poultry farms, increased between 2 to 2.5 degrees Fahrenheit, on average, between 1901 and 2017. By 2080, temperatures in the Chesapeake Bay watershed are projected to increase by 4.5 to 10 degrees, posing a serious risk of heat stress to farmworkers and livestock.

As the post discusses, rising temperatures can hurt farms in several ways. Warmer temperatures make for a longer growing season, which may temporarily promote higher crop yields but can also stress water resources and result in additional fertilizer application, which is not what the doctor ordered for the Bay’s nutrient pollution problem. Increasing temperatures can also create an environment primed for new weeds and pests, threatening crops and creating a demand for still more hazardous pesticides. Heat stress may also disrupt bodily functions of livestock and make them more susceptible to disease.

Rising temperatures can also affect farmworkers themselves. Direct sunlight in expansive fields can increase the heat index, or “feels like” temperature, by up to 15 degrees, and clothing layers used to protect against pesticide and other chemical exposures can add another 12 degrees. The resulting excessive heat exposure can cause illnesses ranging from cramps to death. It can also elevate the risk of injuries caused by cognitive impairment or generate other hazards such as fogged-up safety glasses.

In the United States, farmworkers die of heat-related causes at approximately 20 times the rate of workers in all other civilian occupations. The federal Occupational Safety and Health Administration (OSHA) encourages heat stress prevention measures, such as providing drinking water and shade, and training workers to recognize the signs of heat stress. However, the agency has declined to require such measures, failing to adopt an enforceable standard that would protect workers from exposure to excessive heat. Research also shows that many employers fail to implement proper controls or training, one reason why so many farmworkers die from heat stress. Plainly, OSHA's "encouragement" is not as effective as an actual standard would be.

Working to fill that void, in May, the Maryland legislature enacted HB 722, which directs the state’s Occupational Safety and Health agency (MOSH) to develop and adopt a standard that requires employers to protect workers from heat-related illness caused by heat stress, with a deadline of October 2022. This is a major step forward in protecting Maryland workers. To make the rollout of the new standard most meaningful, MOSH must also ramp up enforcement efforts to ensure employers are implementing the new safeguards and providing necessary training.

MOSH should also adopt guidance and informational materials for employers and workers and assist employers with incorporating the new standard seamlessly into their workplaces. Likewise, MOSH should remind workers of their right to raise concerns about heat stress, free from retaliation, and pay special attention to whistleblower complaints related to heat concerns as the agency moves forward with the new standard.

One heat-related necessity that farmworkers across the country have long advocated for is access to adequate shade. While permanent structures are absolutely necessary, and MOSH should require them as part of its new standard, they should be coupled with another intervention that may provide co-benefits for the environment, livestock, and farmworkers: riparian forest buffers.

The state's Department of Agriculture defines a riparian forest buffer as “an area of trees, woody shrubs, and other vegetation located adjacent to and up-gradient from waters of the state” – shady places uphill from water, in other words. To encourage them, the department offers grants to plant riparian forest buffers through the Maryland Agricultural Cost-Share (MACS) Program, which helps farmers implement measures to prevent soil erosion and protect water quality in the state’s streams and rivers and the Chesapeake Bay.

Such buffers help achieve these environmental goals because tree and plant roots filter nutrients and pesticides, stabilize banks from erosion, and slow the flow of surface water, allowing sediment to settle before reaching a stream. Beyond that, however, canopies formed by trees and other plants in riparian buffers provide shade (and other cooling effects through evapotranspiration) to livestock and, at least temporarily, to farmworkers. As anyone who's sought shade on a hot day can attest, that can make an enormous difference. Studies prove it, finding that peak air temperatures in tree groves are 9 degrees cooler than in open areas and that air temperatures over irrigated agricultural fields are 6 degrees cooler than air above bare fields.

The Chesapeake Bay Program partners (Maryland, Virginia, West Virginia, Pennsylvania, Delaware, New York, and the District of Columbia) have committed to increasing riparian forest buffer coverage in the watershed. In 2014, the Chesapeake Bay Watershed Agreement reaffirmed a 2003 goal to restore 900 miles of riparian buffers throughout the region. However, despite a spike in buffer miles planted in 2016, progress has slowed in Maryland in recent years. One encouraging development is the enactment of Maryland’s SB597 in May (on the same day as the MOSH heat stress directive), which altered the funding criteria under the MACS Program to ensure that “fixed natural practices” such as riparian forest buffers and tree plantings on agricultural land are adequately and continuously funded.

What remains to be seen is whether these changes, and perhaps more importantly, MOSH’s new heat stress standards, are enforced and measurably improve conditions for farmworkers.