Familiar Georgia may melt away

Nineteen years ago, we brought two very young children — the youngest a newborn — to our family’s new home in Atlanta. Today, they are all but grown.

Technically, they’re not Georgia natives. But this is all the home they ever have known. The rhythms of this region are their rhythms; the turn of the seasons and the turn of the roads are as familiar and instinctive as the sound of their mother’s voice.

JAY BOOKMAN
MY OPINION

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They know the hot, muggy days of summer, the sweetness of the long Atlanta spring, the tropical downpour of a thunderous summer storm.

Their deep, intimate connection to place is foreign to their father, whose peripatetic childhood was spent on three continents and in every region of this country.

Over the course of two decades, of course, some things do change. Businesses appear and disappear; old buildings are replaced by new, taller structures; even friends and neighbors sometimes come and go.

But things that ought to be more permanent also seem to be changing. The winter ice storms that seemed frequent in our early years in Atlanta don’t occur very often if at all anymore, and the spring blossom of azaleas and rhododendrons seems to come earlier and earlier.

That anecdotal observation was confirmed in a report last week by the U.S. Global Change Research Program, a consortium of federal scientific agencies. The report focuses on the impact of climate change region by region.

Here in the Southeast, the report notes that the annual average temperature has risen by 2 degrees Fahrenheit since 1970, with most of that change occurring in the winter months.

But the changes ahead may be far more drastic, to the degree that they alter the very character of North Georgia. If emissions of climate-change gases grow at a relatively slow rate, global climate models project a 4.5-degree increase in average annual temperatures in the Southeast by 2080. If emissions increase at a high rate, summer temperatures here will rise by 10.5 degrees.

According to the report, computer models also project extended droughts but more intense rainfall when it does come.

Changes of that magnitude, occurring far more rapidly than any natural climate change in the meteorological record, would dramatically alter the environment for human beings and for most animal and plant species that we associate with North Georgia.

In January, for example, the research program released a report on “ecological thresholds,” the point at which shifts in climate and other factors can “cause changes to propagate in a domino-like fashion that is potentially irreversible,” producing a whole new ecosystem.

As an example, the report cites what happened here in the Southeast in spring 2007, when an oddly warm spring “led to bud-break and development of forest canopy 2 to 3 weeks earlier than usual.”

A hard freeze that April dropped “the low daily temperatures well below freezing for several days,” the report noted. “The freeze killed newly formed leaves, shoots, and developing flowers and fruits and resulted in a sharp drop in vegetation greenness across a large swath of the Southeast.”

According to the report, such events are occurring more often. While springs become warmer, the date of last freeze is staying steady, which could force significant changes in vegetation.

That same report also explores the situation in the Chattahoochee-Apalachicola rivershed, which supplies most of the metro region’s water.

“Analysis of projected future water withdrawals and climate change for the Chattahoochee-Apalachicola river basin indicates that by 2050, minimum flows will drop below (minimum thresholds for fish spawning) for at least 3 months in summer in some areas,” the report said, a change that could affect 75 percent of fish species in the river.

Again, change is inevitable. But the transformation that may loom for North Georgia and the rest of planet Earth may make it a hard place to recognize.

Jay Bookman, an Opinion columnist, writes Tuesday and Friday. Reach him at jbookman@ajc.com.