Climate Change Out of USDA's Comfort Zone

By DAVE FISHER/ecoRI News staff

A few weeks ago, the U.S. Department of Agriculture (USDA) released a revised plant hardiness zone map. This map is an essential tool for gardeners and farmers for planning seeding and crop-rotation schedules. The new map is more accurate — down to a half-mile square — than the previous rendition because of expanded data set available through more monitoring and a longer time frame of collected data, 30 years as opposed to 15.

Enhancing this resource for our nation’s food producers is a step in the right direction, but the expanded data set also showed that, no surprise, it’s getting warmer. Most hardiness zones in the lower 48 are now, according to the USDA, about 2.5 degrees warmer, a shift of about half a planting zone. This shift in average temperature opens the door for food growers to have a longer growing season, and to plant a wider array of crops — though I don’t think that we’ll soon have Del’s lemonade made with Rhode Island-grown lemons. Warmer air and water temperatures also provide an inroad to invasive species that previously couldn't have survived or thrived in New England’s climate.

Again, this shift in zones comes as no surprise to those of us who understand the impact of our industrialized society on the natural processes of the planet, but the USDA’s media blitz, if that’s what you want to call it, shows a disturbing lack of any mention of the greatest problem of the Industrial Age — climate change. In fact, not only does the official USDA press release not mention climate change, the language in the missive actually implies that the shift in zones is somehow due to advanced monitoring and more data.

Compared to the 1990 version, zone boundaries in this edition of the map have shifted in many areas. The new map is generally one 5-degree Fahrenheit half-zone warmer than the previous map throughout much of the United States. This is mostly a result of using temperature data from a longer and more recent time period; the new map uses data measured at weather stations during the 30-year period 1976-2005.

Seriously? The shift is a result of using better scientific methods?

Let’s not kid ourselves. The shift is a result of the millions of tons of gases and particles that we pump into the air every year that trap heat in our atmosphere, causing the planet to warm and our oceans to acidify at an accelerated rate. How can the USDA, the overseer of an industry that recent reports show creates 20 percent of the world’s greenhouse-gas emissions, release a map based on long-term data gathered through enhanced techniques that shows evidence of a continental shift in average temperature and not mention the root cause of the problem?

Given that, I’m offering an addendum press release for the USDA to use at their discretion:

"Advanced long-term monitoring of temperature patterns in the United States have prompted the USDA to redraw the hardiness zone map, adding two zones, and due to an upward trend in average temperatures accelerated by anthropogenic climate change — the majority of the U.S. will shift about a half-zone.

The USDA understands the impact that agriculture has on our climate, and vice versa, and is committed to helping our nation’s farms and farmers mitigate and adapt to the future climate by helping to reduce their dependence on fossil fuels, transition to sustainable and restorative work and conservation practices, providing funding for prevention and removal of invasive species, and supporting regional food systems including transportation and processing concerns."