Climate Witness: Olaf Gradin, USA
I am Olaf Gradin and I have lived in northeast Georgia for most of my life; experiencing the local ecology and ever-changing Georgia weather, season after season. I am a technologist, but have always been interested in horticulture and our natural world. In my early years, I moved from state to state with my mother and brother.We took up residence in a variety of climates from California, through Arizona and Texas, to the eastern United States where I am today. I live with my wife and child, with another on the way. I have worked for a financial services organization for the last four years as a solutions architect in information systems.
The lake that changed it all
Lake Sydney Lanier is a man-made lake formed from the completion of the Buford Dam in 1956. It is fed by the Chattahoochee and Chestatee Rivers. This lake was developed to bring greater commercial and tourism opportunities to the neighbouring cities, as well as to serve as a reservoir for cities as far away as Atlanta.It is responsible for an economic boom in cities such as Gainesville (Georgia) that have capitalized on its resources – real estate, fishing, luxury yachts etc – and was the location of the 1996 Summer Olympics rowing venue.
The lake has been a source of enjoyment throughout my life here as well. As children, it was the local swimming hole and fishing spot for me and my friends. As an adult, I continue to make use of the lake, and have a boy of my own to take swimming.
A pitiless drought, Lake Lanier falls to record levels
Starting early 2007, Lake Lanier has received the brunt of a serious drought in the south eastern United States. In its fifty-odd years of existence, it has never fallen to the level recorded just last year. Along Lake Lanier's expansive 1,114 km shoreline, the water level dropped over 6 m in just 7 months. In the spring of 2008, typically a time in which the previous year’s water losses are recovered, the lake sat at a point 4 m lower than its planned “full pool.”
This was in direct consequence to two main factors. Much of Georgia was in a year-long severe drought state (1) and water from Lake Lanier was being released to neighbouring cities and states (2) to help with the consequences of the drought. Atlanta may well be the largest single consumer of the lake’s water for its population, and its population growth is not appropriately bound by the water on which it feeds.
Impacts of the drought on the lake
Through the catastrophic drought, Lake Lanier exposed large areas of formerly submerged land area from within narrow coves and inlets. With so much exposed lake bed surface, plants were quick to take root in the higher, nutrient-rich soil. The plant life explosion may ultimately build-up the shoreline levels through erosion, which in turn will force the lake inward and create swamps at its edges. The exposed shoreline, much of which is a clay/sand mixture, will erode heavily into the lake, filling it from the bottom up. This process normally occurs over many decades to man-made lakes, although the effects of the drought have accelerated this action tremendously. It is thought that the lake’s longevity has been seriously impacted by the results of this drought.
Community, business disrupted
The lake is a source for many tourism advertising campaigns that the city runs, but the former beauty in the photographs no longer match reality. Boating and boat docks are a big part of the lake’s commercial avenues. Many boat dock builders were unable to weather the drop in business and have closed their businesses. Indeed, there were entire marinas that could maintain only a single slip to service docking rentals. What once was valuable lake-front property today is only a view onto the exposed shores, affecting real estate values.
Local weather affected
The drought has also affected the local weather significantly when compared to the nearby metropolis of Atlanta. The lake has always provided a kind of temperature moderation effect to the towns it connects, cooling the air during summer and warming it in the winter. But with the major drop in the lake’s water level, these benefits are no longer obvious. This is most noticeable during the summer months – leeward breezes do not bring the comfort they once provided. Counter-intuitively, the winter months actually remain warmer. Snow fall has dwindled to near non-existent levels.
Tackling the impact of the drought
As of the summer of 2008, the government has maintained long-term level IV drought status on 55 counties of northeast Georgia. Water use restrictions have been further defined and some towns have implemented full outdoor water use bans. Even the community has done their part to heal the environment. Groups and individuals have taken it upon themselves to clean up the exposed shorelines of debris and trash before they’re covered again. The community has also made efficient water use and the environment in general, a priority in their daily lives.
The drought has brought about many changes to the local environment, economy, and leisure activities to the towns surrounding Lake Sydney Lanier. When environmental issues have local consequences, it is much easier to see how such things can bring about global changes.
Scientific review
Reviewed by: Dr Michael MacCracken, Climate Institute, USAWhile most of the discussion in the media focuses on the projected shifts in temperature, the regional studies for the US National Assessment indicated that the most important impacts for people and communities resulted from changes in water resources. In regions such as the Southeast of the United States, climate change tends to both reduce the sources of water while increasing the sinks, so in regions where water resources are tight, significant stresses can appear relatively quickly.
On a global scale, warming causes an expansion and poleward shift of the northern edge of the subtropics—the hot and generally rainless belt where air is descending after having its moisture squeezed out resulting in heavy rains in equatorial regions. So, southeastern summers are being dominated by conditions that reduce convective rains. When humid, moisture-laden air does appear, the region is too far from the frontal activity that can trigger thunderstorms. As a result, abundant rain tends to appear only when tropical storms and hurricanes can break through, and these are generally rare and provide flooding (and damaging) rains that lead to much of the water running off rather than sinking into the soils.
Spring rains also tend to become less frequent because the meeting of moist air from the Gulf of Mexico and the cold air outbreaks that trigger strong convection (and even tornadoes) are occurring further to the north. Basically, the favorable conditions of the past are shifting toward the north—and reduced
In addition to less rain, warmer temperatures increase evaporation, and not just of surface moisture. Although the increased CO2 concentration helps to improve the water use efficiency of plants, to survive, the forests of the Southeast pull moisture from deeper down, drawing out soil moisture and pulling down the water table (and so lake levels). At the same time, longer and warmer periods of high temperature lead to increased demand for water, by people, industries, landscaping, cooling towers, and to keep river water flow and temperatures suitable for fish and other wildlife. In addition, given how flat the region is, as sea level rises, additional river flows will be needed to keep salt water from pushing upstream into estuaries and wetlands.
Overall the experiences described by this Climate Witness are consistent with the current science in this area of the United States.
References:
US National Assessment (Southeast region).
An updated US national assessment, which has a southeastern component, is due out in early 2009. It should become available at http://www.climatescience.gov/ and at http://www.gcrio.org/library/, both of which also have some useful reports at present.
Current conditions are summarized at http://www.ncdc.noaa.gov/oa/climate/research/2008/oct/us-drought.html
US Climate Change Science Program- Weather and Climate Extremes in a Changing Climate
All articles are subject to scientific review by a member of the Climate Witness Science Advisory Panel.
Olaf Gradin, Climate Witness, US
Lake Sydney Lanier under severe drought conditions.
Through the catastrophic drought, Lake Lanier exposed large areas of formerly submerged land area from within narrow coves and inlets.
Lake Lanier is a Army Corp. of Engineers Managed reservoir. If the levels exceed the full-pool value, a dam can be managed to release water to cities down river, and ultimately the ocean.
Since the drought, this recent season of rain has been the first time that the lake returned to its full pool level. Denizens of northeast Georgia are all pleased to have the rainfall that we've had - insofar as it has eased the drought state - and do not foresee "praying" for global warming. Be that as it may, parts of south western Atlanta were impacted greatly by recent storms and experienced damages from flood waters.
There are consequences on either side in the case of extremes. Nobody wishes for droughts, nor do they appreciate flooding. However, as pointed out in the evaluation offered by Dr. MacCracken, one often leads to the other.
What was that about the Lake Lanier levels? Yeah, I didn't think so. You will be praying for global warming in a few years.http://lanier.uslakes.info/Level.asp