We all like to have a good moan about the weather. Our grandparents tell us that summers are never as sunny as they used to be in the good old days. Well, according to research published today, it turns out that summers aren’t the same temperature today as they were when our grandparents were young. They’re warmer.
A study published today by 45 scientists from 13 countries uses evidence from tree-rings to put our modern European summer temperatures into the context of the last 2,000 years.
Each year a tree lays down a ‘ring’ of new wood, which creates the ring pattern we’re all familiar with (image right). Rings alter in colour and density depending on the year’s growing conditions – a fast growing tree lays down lighter and less dense rings than a slow growing one. By comparing recent tree rings both to temperatures recorded by today’s thermometers and to ancient tree rings, scientists could deduce the temperatures of summers going back to more than 2,000 years
It turns out that temperatures over the last two millennia were more variable than we first thought (see graph). Summers were relatively balmy in Roman times (good weather for togas), followed by a cooling period that continued until medieval times. Shortly after, Europe entered a so called ‘little Ice Age’, which continued from the 1300s all the way through to the apparently chilly reign of Queen Victoria in the 19th century.
European summer temperature variations 137 BCE to 2003 CE and associated uncertainties. Copyright: CC BY-SA 4.0 J.P. Werner/EuroMed2k Members.
When these variations are compared to our rapidly warming modern temperatures, it becomes clear that what we’re experiencing today now lies outside of this natural variability. It shows us that while some change in temperature is normal over time, the kind of big changes we are now experiencing is anything but natural. The coordinator of the study, Professor Jürg Luterbacher from the University of Giessen in Germany, says that we can use this new information to help predict the impacts of future global warming.
Based on this latest research, it looks like extremes in weather are set to continue and the summers will be getting warmer. Hopefully, with studies like this our ability to predict these extremes will improve, helping is to cope with what’s to come. I can’t help but wonder, though, what the people of a thousand years from now will think when they see the tree rings being made today. By then, even our extreme weather may seem like ‘the good old days’. Or maybe we’ll have found a way to save our ailing planet – touch wood.