Luckily, some of these climate change questions can be “illuminated” using our calculated climate extreme indices.
These 26 climate extreme indices are standard, meaning that how they are calculated are strictly defined so researchers can easily compare results over different regions and/or time periods. However, we can still use the indices in different ways that can help us answer questions for which there are no climate extreme indices.
What do I mean?
One of my favorite climate extreme indices is the Growing Season Length. This index convincingly, and statistically, shows that the growing season has increased over the last 115 years (Fig 1).
Well, what about the amount of days not in the growing season?
We can roughly say is that the “non-growing season” length is a proxy for winter length. And the length of the winter is something many climate scientists, ecologists, and ski enthusiasts (among many others) may be interested in knowing.
While we do not have an index for winter length, we can use our Growing Season index to calculate a new index. Simply, the length of winter is 365 days minus the growing season length. (Note, every 4 years that is 366 days!)
For example, our growing season was 328 days in 2014 so our winter length was 37 days.
That’s pretty interesting!
Since the Winter Length is basically the inverse the of Growing Season Length, the negative trend makes perfect sense (Fig 2). We can observe that the length of the winter has decreased since the 1900’s, implying that our cold season is getting shorter. On average, we now observe 30 less winter days compared to the 1910’s.
There are a few reasons why you may care about a shorter winter, although I am sure a few people are thinking to themselves “a shorter winter? That’s great! Bring on the beach!” One example we previously used deals with fruit trees; fewer freezing days often results in a smaller fruit yield. Another example is that pests now have a longer season to thrive, and a short winter may even let new pests move in.
Overall, creativity often gets a negative association in science since it can be interpreted as “made up.” However, creativity is fundamental to the thinking process! Victoria Coles, one of the lead scientists on this project, was the first to look at the Growing Season Length and realize that it could also be seen as a measure of winter length.
The bottom line, scientists can be creative and produce solid research at the same time!