Summary

No evidence was found of a significant change in monthly mean air temperatures over the full time series [1993-2012]. There was a marked increase in summer precipitation. These are the key points made in the 2016 special issue paper.
  • Changes in a range of weather and atmospheric deposition indicators measured at terrestrial ECN sites between 1993 and 2012 were analysed.
  • No evidence was found of a significant change in monthly mean air temperatures over the full time series.
  • However, there was a marked increase in summer precipitation, linked to an unusually prolonged directional shift in the summer North Atlantic Oscillation (NAO), while the intensity of extreme precipitation events also increased.
  • Arguably the most ecologically influential changes in the environment of ECN sites over the past two decades have been substantial reductions in acid deposition. Sites experienced large declines in the concentration of sulphate in precipitation. Much of the wider UK countryside is likely to have experienced similar trends over the period.
  • Concentrations of nitrogen species, i.e. nitrate (NO3+) and ammonium (NH4+), also fell slightly at several sites.
  • Over the past 20 years, regional scale drivers of environmental change are likely to be responsible for both widespread increases in soil solution pH, reflecting reductions in acid deposition, and wetter conditions over the middle of the growing season.

 

Reference: Monteith, D., Henrys, P., Lindsay, B., Smith, R., Morecroft, M., Scott, T., Andrews, C., Beaumont, D., Benham, S., Bowmaker, V., Corbett, S., Dick, J., Dodd, B., Dodd, N., McKenna, C., McMillan, S., Pallett, D., Pereira, G., Rennie, S., Rose, R., Schafer, S., Sherrin, L., Turner, A., Watson, H., Poskitt, J. and Tang, S. (2016). Trends and variability in weather and atmospheric deposition at UK Environmental Change Network sites (1993-2012). Ecological Indicators, 68, 21-35. DOI: 10.1016/j.ecolind.2016.01.061.