Scottish Marine and Freshwater Science Vol 9 No 4
In this report we have described the status of the physical conditions in the seas around Scotland in 2016 and examined the variability and trends in the last decade, and further into the past. Although the global climate trend is one of warming, when examining data at a regional level, there are many different drivers which introduce variability at multi-decadal and decadal timescales. Because of the complex linkages between ocean conditions and the atmosphere, multi-decadal variability can be observed not just in air and sea temperatures, but also in long-term rainfall and sunshine trends. The long-term pattern of variability in North Atlantic temperatures makes it quite difficult to separate observed changes caused by Global Climate Change from changes caused by natural variability, particularly in cases where observations only extend back 30 years or less. Change observed at a regional level can be more extreme and more variable than the smoothed trend we see in the global average temperature trend. Despite the long-term warming trend, it is likely that Scotland’s seas will experience periods of enhanced warming, periods of reduced warming, and even periods of cooling. Nevertheless, climate change induced by human activities will cause a warming trend on global and long-term time scales. Both air and sea temperatures around Scotland have warmed at a similar rate to the global pattern of century-scale warming as reported by the IPCC in 2014. At a multi-decadal scale, during the 1970-1980 to 2010 warming episode, air and sea temperatures across Scotland warmed at a rate faster than the global average. Regional variations, and variations on shorter time-scales, to these general observations can be found in the many time-series within this report.