Climate change threatens apple production in Pennsylvania

June 23, 4:12 PMPittsburgh Gardening Scene ExaminerRose Field

As one of the critical variables beyond our control, weather catches the interest of home gardeners, but to commercial farmers, weather fluctuations can imperil their very livelihoods. Now global climate change has added a new factor to the old problems.

Fall means apple harvest time throughout rural Pennsylvania. From farm stands to wholesalers, apples represent sixty million dollars worth of revenue to Pennsylvania growers, making the state America's fourth largest producer.

About one-fourth of the crop goes to market as fresh fruit, while the rest is processed into juices, applesauce and other foods. With 500 millions pounds of Pennsylvania apples flowing into the market each year, production has a large impact on our nation's food supply as well as the state's economy.

This important industry could be markedly transformed over coming decades due to climate change, according to an assessment released by the Union of Concerned Scientists. The listing of advisors, contributors and reviewers who helped compile this report reads like a Who's Who of scientists from Penn State, Carnegie Mellon, other universities and experts from several governmental agencies. The team studied dozens of areas of probable climate change impact including the economy, health, recreation and habitat.

Using data from both peer-reviewed research from Pennsylvania scientists and national sources on climate, the report offers projections based on two scenarios. The first details what will happen if we allow greenhouse gas emissions to go unchecked. In contrast, the report then shows how a second, lower-emissions model could mitigate the impact of man-made damage.

Apple orchards dot the land in every region of Pennsylvania, but are especially important in the southeastern part of the state. Adams county is the heart of apple growing. Macintosh, Granny Smith, and other popular varieties flourish here. Apples are among several types of fruit which require a certain number of hours of winter chill to properly set fruit. The report notes that between 800 to 1,200 chilling hours are necessary for most types grown in the state.

If the higher-emissions scenario continues, only about 50-60% of the winters in the southeastern part of Pennsylvania, including Adams County, would have 1,000 chilling hours by mid-century. By late century, only the northern-most counties would have enough cold hours to produce apples.

In the second, lower-emissions scenario, growers could count on enough cold weather to grow apples until late in the 21st Century. Farmers, food production markets and consumers could slowly adapt to varieties which require fewer chilling hours.

The entire report from the Union of Concerned Scientists, Climate Change in Pennsylvania, Impacts and Solutions for the Keystone State is available online.