Ruth Monfries: The Botanics is managing the effects of climate change

Picture: TSPL
Picture: TSPL
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Recent weeks have seen climate and weather records topple at an extraordinary rate: the Met Office, Nasa and NOAA (the United States National Oceanographic and Atmospheric Administration) all announced they had found 2015 to be the warmest year on record.

The Met Office figure beat the previous record, set in 2014, and 2016 is expected to be warmer still. In 2015, for the first time, average CO2 (carbon dioxide) levels in the atmosphere were regularly above 400 parts per million.

The exceeding of global temperature records has become the norm. Of more immediate concern is the devastation wrought by a series of storms this winter. December, the warmest and wettest on record in the UK, brought Storms Desmond, Eva and Frank.

The latter caused widespread destruction in Scotland; the flood wave on the Dee from Braemar to Aberdeen was the biggest in living memory. Then, January saw the tail end of Storm Jonas, which had caused “snowmageddon” in the US, closely followed by Storm Gertrude, shutting down transport links and leaving thousands without power. February has seen no let up, with the arrival of Storm Henry.

These global and local records are not unrelated. We have always seen seasonal Atlantic storms. But now there is a critical difference. As storms build over the Atlantic, more water evaporates in the warmer atmosphere, so when the storm clouds reach land, they dump greater quantities of water.

The rainfall associated with storms is more intense. This causes waterlogging so that ground is already saturated when the next rainfall arrives. That can make the difference between flood defences holding or not. The impacts of climate change are most apparent in Scotland not as gradual warming but by weather extremes becoming more intense and frequent. And the practical consequences of our changing climate are now sadly familiar – such as landslides triggered by heavy rainfall causing repeated closures of the Rest and Be Thankful on the A83. The Royal Botanic Garden Edinburgh (RBGE) has four Gardens across Scotland, where horticulture staff have been aware of climate change for longer than most.

What can we do to lessen these impacts? We need to reduce emissions of CO2 to avoid catastrophic climate change. But our climate is already changing and will continue to be affected as levels of CO2 in the atmosphere will remain high for many decades. We need to adapt to cope better with changing 
conditions.

With respect to excess rainfall, this includes adopting a sustainable and more integrated approach to flood management. In upland areas, restored peatlands and regenerated forests can better soak up excess water and release it gradually to lessen flood peaks. In downstream areas, sustainable urban drainage systems include using permeable surfaces and green infrastructure, such as wetlands and ponds, to reduce excess surface water.

RBGE is adapting. In 2014 each season saw temperatures almost 1.5C warmer than average, snowdrops (Galanthus nivalis) that normally bloom in February were in flower on New Year’s Day 2015, the mildest start to a New Year since 1916. The first cut of the lawns was on January 6! But, May brought much lower temperatures than usual; June remained cool but gusting winds dried out leaves.

Dry weather, sunshine and cool nights in September and benign weather in October saw a spectacular season for autumn foliage. Then, we were hit through winter by frequent dangerously high winds causing garden closures.

As the seasonal pattern relied upon by RBGE horticulturists becomes less reliable, management of the garden landscape becomes a cycle of predicting, monitoring, reacting, responding, learning, and adapting. Each new challenge holds an opportunity for improved resilience and practical action. As infrastructure is adapted to cope with changes, new opportunities are also being identified. At the core of RBGE’s existence are research and conservation. Rising temperatures may provide opportunities to grow and conserve yet more exotic species: many of which are endangered in their native habitat.

l Ruth Monfries works at RBGE on behalf of the Scottish Government’s Centre of Expertise in Climate Change (ClimateXChange). She monitors and advises on Scotland’s climate adaptation policy and its implementation in practice. RBGE is a case-study for good practice in adapting to climate change: http://www.adaptationscotland.org.uk/Upload/Documents/R oyalBotanicGardensEdinburghadaptationcasestudy.pdf