From roughly the year 1200 to the year 1800 the Earth was thrown into a Little Ice Age. The Little Ice Age was a period of time in human history where many people suffered at the hand of a climate we did not understand or prepare for. This can happen again. The question is why did it start and when will it happen again? I hope this blog answers some of these questions.
- Crop Failure:
- Towns disappeared:
- Transportation change:
- Iceland had ice surrounding it for miles in each direction. Harbors closed.
- Geographic change:
- Decrease in population:
- World population increase slowed and decreased in many areas, especially in Europe.
- Armies walked across water:
- Colonies vanished:
- Permanent snow on Ethiopian mountains:
- Ice in June:
- Native American crisis:
- Glacier advancing:
Now that we have the effects what were the potential causes of this Little Ice Age?
1. The Sun- The Sun develops something called sunspots on its surface. They are basically “cooler” areas of the Sun. In response to the cooler area with less convection there is a large amount of magnetic activity. Sometimes this magnetic activity is released in a massive explosion called a CME. These are what give Earth radiation and cause the northern lights.
If sunspot activity is reduced there are less CME’s and therefore a smaller amount of radiation/heat reaching Earth. There was a large reduction in solar activity during the Little Ice Age. Every 11 years the Sun reaches its solar maximum in terms of sunspots. We are at solar maximum.
3. Thermohaline circulation- The large circulation process of water in the Earth’s oceans is elaborate and vital to our climate. Salt water is heavier than fresh water. Because of this a circulation is created in the ocean that carries warm water from the equator north to the coast of Europe. This is why England has a climate much like the northeast states in the United States (warm water brings warmer air). If the circulation shuts down England resembles northern Canada.
The theory is that a large amount of fresh water, created by the warming period immediately preceding the Little Ice Age, increased the amount of fresh water from icecaps in the ocean. This in turn shut down the circulation and caused the northern hemisphere to cool.
4. Orbital patterns- Cycles in the Earth’s orbit around the Sun can create cooling and warming periods. If this is true then the cooling process will continue until we reach another ice age in around 4,000 years. This is a normal pattern on Earth.
So what? Why should any of this matter today?
The reason I bring this up is because, contrary to the seemingly apocalyptic reporting of CME's from the Sun by the media, the Sun should be at its 11 year maximum for sunspots (which produce CME's). Though we have had some sunspots there are hardly as many as previous solar maximums. This indicates that the Sun may be entering a solar minimum, much like that during the Little Ice Age. If you followed earlier, fewer sunspots mean less heat reaching the Earth.
What does this mean for us? Many scientists believe nothing. The impact of the Sun is far less than the impact of greenhouse gasses in the atmosphere. The gasses will offset the cooling process and prevent another Little Ice Age.
Other scientists disagree. The Sun is the MAIN source of heat for the surface of the planet. Some heat is produced by Earth's core but the amounts pale in comparison to the energy sent by the Sun. Taking this into account a reduction in solar output would coincide with a direct decrease in latent heat on Earth. This would lead to a cooling of the planet and in turn a Little Ice Age that may, once again, have similar impacts as the one last millenia. Given the 7 billion people on Earth, there would mass food shortages and large geographical changes, among other things.
If a major volcano explodes, such as the super volcano under Yellowstone, then the Earth will certainly be thrown into another Little to full fledged ice age.
What do I think?
Global warming is increasing at a rate unprecedented and it is being contributed to by humans. In addition to our own contributions there are changes that we are trying to understand on Earth. Earth goes through patterns and right now it should be cooling, not heating up. Still, the Sun, if it continues at solar minimum, may quell the speed of global warming in the coming decades due to the decrease in radiation reaching Earth. Will we see an ice age on the level of the Little Ice Age? No. We need to monitor this closely.
The bottom line: Do not think that tomorrow we will see glaciers crushing towns across the world. Any climate change takes decades to centuries to complete; however, we should be concerned with the increase in global temperatures and in turn what impacts this will have on our Earth. Barring any major volcanic eruptions or other unforeseen events, I do not believe we will see another ice age for thousands of years. In the end the only thing we can do is live in the moment and hope for the best. The Earth will do what it wants and we are just along for the ride!
Please feel free to comment. This took a long time to research and started as a sentence but quickly exploded into an essay. Thanks for reading!
Emmanuel Le Roy Ladurie (1971). Times of Feast, Times of Famine: a History of Climate Since the Year 1000. Barbara Bray. Garden City, NY: Doubleday.
Lamb, HH (1972). "The cold Little Ice Age climate of about 1550 to 1800". Climate: present, past and future. London: Methuen.
Stone, Richard (2004-11-19). "Iceland's Doomsday Scenario?" http://www.sciencemag.org/content/306/5700/1278
Broecker WS (February 2000). "Was a change in thermohaline circulation responsible for the Little Ice Age?" http://www.pnas.org/content/97/4/1339
Rose, David (2012). “Forget global warming…” http://www.dailymail.co.uk/sciencetech/article-2093264/Forget-global-warming--Cycle-25-need-worry-NASA-scientists-right-Thames-freezing-again.html
Mandia, Scott. “Influence of Dramatic Climate…” http://www2.sunysuffolk.edu/mandias/lia/little_ice_age.html
“Little Ice Age” http://www.eh-resources.org/timeline/timeline_lia.html