I was complaining to one of my favorite people this weekend about the lack of winter weather here in Virginia (let’s be real, 65 degrees in January is weird), and he said to me, “We just need another little ice age.”
A little what? You heard right – a little ice age. I didn’t know such a thing existed, and I don’t think I want one if it’s anything like an honest to goodness ice age. Well, according to Wikipedia, the Little Ice Age was a specific period of cooling that occurred right after the Medieval Warm Period. Although not everyone agrees on the exact time frame, the Little Ice Age (LIA) is generally thought to have extended from the 16th century to the 19th century. The LIA was not experienced uniformly around the globe or even across the Northern Hemisphere; however, there are reports of cold spells during that time period throughout the world. The LIA was primarily characterized by expanding glaciers, unpredictable weather, and cooler winters in parts of Europe and North America. Winters got so cold that the River Thames would freeze, and an annual frost fair was held on the river from 1607 up until 1814. At one point, the Baltic Sea even froze over, and tourists could ride from Poland to Sweden on the ice, stopping at seasonal inns along the way.
So, what could have brought on this Little Ice Age? Many will undoubtedly say that it is all part of the Earth’s natural climate cycle. Since the end of the last real ice age 12,000 years ago, sediment patterns from glacial melting and re-freezing show that a series of 1-2°C (2-4°F) cooling events has been occurring every 1,500 years or so, the most recent of which was the LIA. However, those cycles are so often brought on by something, whether it is natural or anthropogenic. Scientists have tentatively identified 5 possible causes for the LIA:
- Cyclical lows in solar activity (The period between 1645 and 1715 is known as the Maunder Minimum and is characterized by uncharacteristically low sunspot activity.)
- Heightened volcanic activity (When volcanoes erupt, their ash can reach high into the atmosphere and block incoming solar radiation.)
- Changes in ocean circulation (After the Medieval Warm Period caused glacial melting, a large amount of fresh water was likely introduced into the North Atlantic Ocean, thus causing the thermohaline circulation (THC) to slow down.)
- Decreases in human population (We’re not the only generation affecting climate – the Black Death caused a massive decrease in the populations of Europe, East Asia, and Middle East, which subsequently led to a decrease in agriculture, reforestation, and less carbon dioxide residing in the atmosphere.)
- Orbital cycles (Caused by the force’s of Earth’s orbit around the sun, we have been experiencing cooling at a rate of .02°C per century for the last 2,000 years. Apparently this trend would typically be expected to continue for another 4,000 years and lead to another full ice age, but our recent and sudden rise in global temperature may bring that occurrence into question.)
Maybe I’m the only one who finds this interesting, but I didn’t realize that ice ages came in varying degrees and that we had experienced one so recently! We hear about our climate’s natural cycle, so perhaps it is only natural that the LIA would be followed by another period of warming like we have seen in recent decades? As you can see from above, the climate’s “natural cycle” is affected by so many factors both within and outside of the Earth’s atmosphere, so it seems plausible that opposing forces to those above could be contributing to the current warming period, thus reversing the effects of the recent LIA. However, records indicate that global temperature has been rising much more rapidly this time around. And, National Geographic reports that the average global temperature has risen by .8°C in the last 100 years, but temperature has increased by twice that amount in the Arctic. We may have already been headed toward a natural warming period, but I certainly believe that human activity has augmented that warming.
As for the present, the forecast for tomorrow is 67 degrees…maybe I could go for another Little Ice Age right about now?