Not Writing About How Hot 2014 Was:

Published: 5:27 AM GMT on January 17, 2015

Not Writing About How Hot 2014 Was:

I will be the only climate-change blogger not writing about how hot it was in 2014. Nor will I write about how remarkable this fact might be because there was not an El Niño. I want all of my faithful blog readers to go back to my entry from May 29, 2014, and then paste into comments on other people blogs “We have remained warm, globally, despite relatively cool temperatures in the eastern Pacific. Given the importance of the eastern Pacific to the global picture, even a small break in the cool pattern is likely to lead to globally historic highs.” I’m just that way – a vain, cranky old man making mostly obvious observations.

I will talk a little bit about what this heat means relative to other hot times. I am responding to a comment over at What would happen to the climate if we stopped emitting greenhouse gases today? I will have another piece over at The Conversation at the end of February when it will have been 30 years since the last month whose temperature was below the twentieth century average.

The comment I respond to (you will have to go other there for more context):

“It is difficult for me to understand your premise that humans have evolved to perform optimally in a particular range of global temperature. Humans did well during the Medieval Warm Period (warmer than today) and did well during the first part of the 20th century when the global temperature was cooler than at present.

In fact, some folks who study agriculture think that part of the 20th century "green revolution" can be attributed to increased concentration of atmospheric CO2 and to longer growing periods due to warming global temperature.”

My Reply

Let’s take the Medieval Warm Period (MWP). The most convincing scientific investigations conclude that the geographical extent of the MWP was not global and that it was not warmer than the current times. Also I think it easy to argue that our knowledge of the MWP is Euro-centric. Those details, however, are not important to the foundation of my argument.

To be clear, I used the example of human heat health as a concrete example of a more general fact that agriculture, ecosystems, humans, etc. have evolved to perform well in a certain range of temperature and wetness. If one goes in either direction, too dry-too wet, too cold-too hot then that performance is reduced.

From the point of view of an expansive-minded culture on the European continent, the sustained warmth is a boon and opportunity. Perhaps, they view that God is on their side. Perhaps there is the possibility of wine from Greenland, though I imagine it surely remained a crop of marginal reliability and quality. From the point of view of the native Greenlander it is a disaster. They might adapt to different behaviors of seals and whales and lichens; however, they do not adapt to marauding bands of Vikings. In this little example, the world might indeed be better for the Vikings, but hard to argue that it is better for the Greenlander. Like today we have winners and the, perhaps, dismissed losers.

I think my original point was that climate change would be disruptive. The balances that we have developed will be challenged, and there are very few examples of incremental, peaceful, systematic adaptation to such changes.

Going a little further – as I understand things, the difference between the MWP and the following Little Ice Age was on the order of a half a degree Fahrenheit (see Figure). So in my interpretation of things, we have evidence that half a degree Fahrenheit has significant impacts on agriculture, ecosystems and humans. Presently, we have warmed the planet by, what, three times that amount, and we will be warming the planet at least twice that. This warming is occurring very rapidly. Therefore, the consequences and the disruptions are expected to be large, and the adaptations we achieve will be painful.

There is no evidence that I am aware of that the Arctic realized the large and essentially irreversible changes we have seen today. There is no evidence of substantial changes in sea level; stability in sea level can be linked to societal success because of our affinity for the coasts and sailing around exploring and wreaking havoc. Therefore, today’s warming has far more profound environmental consequences than those associated with the MWP.

In the little world of the Vikings and Greenland, we have ignored what might have been happening in the Sahel, at the edges of the deserts in India and China. In our little Euro-world of the MWP, we did not have seven billion or more people to feed. Therefore, I am quite ignorant of how humans as a whole performed, thought it is generally not a time viewed as the golden age of humans. Today, the number or people and their portfolio of environmental impacts yield a planet that is fundamentally different today than 500, 1000, 1500 years ago.

No one denies that there is a fertilization effect of carbon dioxide. Plants that have famous carbon dioxide sensitivity are poison ivy and marijuana. As with all fertilizers, more is not necessarily better. Some plants respond differently to carbon dioxide. There are strong sensitivities to environmental nitrogen, a pollutant on the scale of carbon dioxide. And while there are some benefits to some plants, the acidification of the ocean is likely to cause disruptions to plant and animal life that make that carbon dioxide benefit look stunningly insignificant.

All we really have going for us is the analysis and predictions of certain warming, ice melting, sea level rise and weather changing. We have knowledge on how to limit our damage and knowledge on how to prepare for what’s coming. We can be smarter than the Vikings heading faithfully and blindly out into the sea and cluelessly starting vineyards.

r



Figure 1: Variability of temperature last 1000 year. From Koshland Climate Museum

Some references:

Spatial expanse of warming

Stable Sea Level and Civilization

Variability of temperature last 1000 years



Please note the comment from Ray Arritt about the factual aspects of vineyards in Greenland ... 20150119

Arritt's comment reproduce here:

"Been lurking here for quite some time and thought to offer a pedantic correction or two on one of my favorite topics.

There's no sign of wine grapes having been grown in Greenland. There's evidence of attempts to grow barley, but even those appear to have been intermittent and limited to small, protected areas. It's just too cold.

The sagas tell of finding grapes during the Vikings' few trips to "Vinland" (literally, land of grapevines) around 1000 AD. The location of Vinland is uncertain but it probably was along the St. Lawrence River or the Atlantic coast somewhere between New Brunswick and New England.

Greenland was not "green" during the Norse era, at least no greener than at present. According to the sagas Erik the Red called his prospective colony Greenland because "he said people would be attracted there if it had a favorable name." Advertising hype, 985 AD."

Comments (169) Permalink | A A A
About The Author
I'm a professor at U Michigan and lead a course on climate change problem solving. These articles often come from and contribute to the course.

Recent Articles

Big Loopy Road Trip: Energy in America Moves On

Big Loopy Road Trip: Energy in America Moves On

I still like the road trip, and last week I drove from Boulder, Colorado to Ann Arbor, Michigan. For two full days along U.S. 34, U.S. 136 and U.S. 36, I did not see a Starbucks, Cracker Barrel or a Whole Foods. Some of the bigger towns had a WalMart, but I was on the lookout for towns that might be big enough to support a Casey’s, literally sputtering into one because aging Subaru-san’s gas seems a l...

Read Article - Comments (75)

Sunrise, Sunset / Sunrise, Sunset / Swiftly Fly the Years

Sunrise, Sunset / Sunrise, Sunset / Swiftly Fly the Years

Here’s an easy prediction for 2015. When we arrive at March 1, 2015, it will have been 30 years since there was a month where the global average surface temperature was below the 20th century average. We are creatures who like our milestones in years and decades and numbers divisible by 5, 10, 25 and 50 (like our currency), and a 30 year average is the definition of climate in the standard of cl...

Read Article - Comments (142)

Wagging the Dog

Wagging the Dog

My piece that was published last week at The Conversation entitled, What would happen to the climate if we stopped emitting greenhouse gases today? has had more than 350K reads – most read science and technology article of the week. Last week in my WU blog, I provided some background material trying to make that piece a little more intuitive. In this blog, I will expand on a couple of ideas that came up in the conversation.

Oc...

Read Article - Comments (57)

Turn Off the Carbon Dioxide Emissions – It Still Gets Warmer

Turn Off the Carbon Dioxide Emissions – It Still Gets Warmer

I have a piece that went up today on a new-to-me website called The Conversation. It’s title is: What would happen to the climate if we stopped emitting greenhouse gases today? I try to explain with not so many words - if we stopped emitting carbon dioxide today, why does the temperature keep going up.

In this blog, I will provide some background material that might make thing...

Read Article - Comments (325)

Previous Entries