According to the United Kingdom's Met Office, which forecasts weather and climate change, for the last decade the plant growing season in England has been 29 days longer than the average between 1961 and 1990.
The Met uses the Central England Temperature (CET) record—the longest continuous temperature log in the world (it's been recording daily temperatures since 1772)—to track growing seasons. Over this multi-century record, six of the ten longest growing seasons have occurred within the last 30 years, with the longest one happening in 2014 at 336 days. By comparison, only three of the 10 shortest growing seasons have taken place in the last century. According to the Met figures, the rate of change to the growing season appears to be rapidly ramping up.
"Between 1861 and 1890, the average growing season by this measure was 244 days, and measuring the same period a century later, the average growing season had extended by just over a week," said Doctor Mark McCarthy, the manager of the National Climate Information Centre, in a statement. "For the most recent ten years between 2006 and 2015, the average growing season has been 29 days longer at 280 days when compared with the period between 1961 and 1990."
McCarthy said that these changes are in line with the broader impacts of climate change.
“The overall rise in the growing season length is consistent with the observed warming across the U.K. of just under 1C since the 1960s," he said.
While it may seem obvious, the growing season is the time of year when conditions are warm enough for plants and other crops to grow. This has been defined as officially starting when average daily temperatures for five days in a row exceed 5 degrees Celsius (41 degrees Fahrenheit).
As the Carbon Brief reports, a longer growing season is not necessarily a good thing for England's farmers. Prof Andy Challinor, professor of climate impacts at the University of Leeds, told the Carbon Brief that while "there is more time in which crops can grow, existing varieties will tend to mature more quickly, meaning the crops will tend to be smaller.”
How a plant responds to changes in climate depends on the type of plant, its life cycle, the time of year, and the general weather conditions, such as how much rain, sun, or frost it's exposed to.
While climate change is widely believed to be making the United Kingdom wetter and subject to more intense flooding, when it comes to frost the data shows that the number of days where the minimum temperature dips below 0 degrees Celsius has been declining in recent decades.
"Although we have fewer air frost days on average than we experienced a few decades ago, the numbers can still fluctuate from year to year," said McCarthy. "Many people will remember vividly the cold spells during 2010 and 2013. In contrast, 2014 recorded very few days of air frost and being the lowest in the U.K. series from 1961."
Wednesday, March 23, is World Meteorological Day and the World Meteorological Organization (WMO) is using the additional attention to highlight examples of how the climate is changing around the world. This year's theme is: 'Hotter, drier, wetter: face the future.'
“Climate change is affecting our natural and human environment," said Petteri Taalas, Secretary-General of the WMO. "Our emissions of greenhouse gases continue to rise, and the temperature of the lower atmosphere and the ocean is increasing."