What global warming can do to us – Part 1

Julian Pfitzner, a friend from Australia, first got me thinking about global warming when he told me fracking for oil and gas contributed to global warming, which he was an expert about. I was stunned because I had worked in fracking for 30 years, so it felt like an attack (though unintentional) on my career.

But this left me with an itch that wouldn’t go away because I wanted to find out if there was any truth in Julian’s opinion. I started to research global warming and its causes.

What I found out jolted me. In my usual way, this writeup is based on data as far as possible. And it’s aimed at layperson thinkers who want to find out more.

Greenhouse gases circulate in the earth’s atmosphere and are given their name because they trap the sun’s incoming heat, which in turn causes warming of the atmosphere. The mechanism is analogous to a greenhouse used for growing plants in a garden.

Four different kinds of greenhouse gases are shown in Figure 1. Carbon dioxide is the main component.

This image has an empty alt attribute; its file name is Types-GHG.jpg
Figure1. Top panel: US greenhouse gas emissions in 2016, by gas type. Bottom panel: US greenhouse gas emissions by economic sector in 2016. See Reference 1.

According to climate scientists, the close tracking in Figure 2 implies that global temperature follows the concentration of carbon dioxide (CO2) in the upper atmosphere. There are some variations, but overall the temperature is tied to the carbon dioxide concentration.

This image has an empty alt attribute; its file name is Temperature-change-and-carbon-dioxide-change-measured-from-the-EPICA-Dome-C-ice-core-in-Antarctica-v2.jpg
Figure 2. Temperature change (light blue) and carbon dioxide change (dark blue) measured from ice cores from EPICA Dome C in Antarctica. Click to source. https://www.ncdc.noaa.gov/global-warming/temperature-change

CO2 concentrations going back 800,000 years are shown in Figure 3. These data are inferred from ice cores by drilling through ice sheets in Antarctica that have been around for a long time. The ice sheets contain bubbles of trapped ancient air. More recently CO2 has been measured directly in the air since 1960.

Note that the end of the graph is a spike where the CO2 level spikes up to 400 parts per million (ppm). This is much higher than all the glacial cycles of Figure 3, in which CO2 concentration remained between 200–300 ppm for the last 800,000 years.

So right now, in 2020, the CO2 level is higher than its been for 800,000 thousand years. But it’s worse than that – other measurements show that its higher than its been in the past 3 million years. Wow! Is the earth entering a new period of history where we’re unsure what could happen? This sounds a bit scary.

But what about global temperature? What’s it doing? The short answer is its going up also — see Figure 4. We are up a bit over 1 degree C in the past 150 years – roughly since the start of the industrial revolution.

But a deeper question is, How fast is the temperature rising? The answer lies in Figure 4. Global temperature and CO2 level have been tracking well and both rising rapidly over the past 40 years.

To answer this we have to rely on models that can predict the future. Many such climate models have been developed and they all give a different answer, as expected because they are complex models. But the models are still able to predict a range of temperatures. Figure 5 shows predictions of global temperature up to the year 2100.


The yellow band at the top of Figure 5 is the range of model predictions through the year 2100 if nothing is done about reducing greenhouse gases (its labeled “No climate policies.”) In small print we can see that in the yellow band the global temperature is predicted to rise by 4.1 – 4.8°C by the year 2100, measured from pre-industrial days.

Let’s take the average to be 4.5°C for simplicity. Since we are now about 1°C above pre-industrial, this predicts an additional 3.5°C higher than where we are now in 2020. We’d like to know how this increase compares with historical data.

This “do-nothing” greenhouse gas situation is very serious. If greenhouse gas emissions are not abated the global average temperature is predicted to reach higher than any time in the previous 400,000 years. And this could happen as soon as the year 2100.

On top of this, the CO2 concentration in 2020 is higher than its been for the last 3 million years, as we explained above.

• This conclusion is sobering because while it depends in part on modeling temperature predictions of greenhouse gas emissions, it also depends on actual measurements of CO2 – and the two appear to walk hand in hand.
• The temperature predictions are based on models, yes, but there is an independent study that has tested the predictions of these models, and concludes the models make valid predictions. See Reference 5.
• It appears the world needs action to reduce greenhouse gas emissions in a hurry.
There is a startling message hidden behind the global warming of Figure 5: if we do nothing to reduce greenhouse gases, by the year 2100 the earth will have entered a new era that it has not been in for the past 400,000 years (almost half a million years). For comparison, note that modern civilization has only been around about 10,000 years. Will our civilization be able to cope with these temperatures by the year 2100?
• This writeup has been adapted from the new book The Shale Controversy (see link to purchase on this page – the price has been reset.)

Feel free to jump over this section… its just more details. For starters, we can compare with 2,000 years of temperature data (Figure I-27) displayed in a book called Inconvenient Facts. The book has assembled credible graphs, based on ice-core data and other methods, that illustrate global temperature history. For example, in 2020 we are already 0.6°C above the highest temperature in the year 900 (the peak of the Medieval Warm period) while in 2100 we would be way off the chart, higher by another 3.5°C.

If that’s not serious enough, we can compare with the last 10,000 years shown in Figure I-30 by the same author. By the year 2100, if greenhouse gas emissions are not abated, the temperature would be off the chart again, and about 2.2°C higher than the peak temperature of the past 10,000 years.

If that’s not scary enough, compare the predicted temperature with the last 400,000 years in Figure I-29 by the same author. If greenhouse gas emissions are not abated, the predicted temperature in 2100 would be a little higher than all the inter-glacial warming peaks of the last 400,000 years.

1. US Environmental Protection Agency.
2. Femke Nijsse, https://foundation.wikimedia.org/wiki/File:Carbon_Dioxide_800kyr.svg, May 2018.
3. Source: NOAA/NCDC. Wikimedia Commons, File: Atmospheric carbon dioxide concentrations and global annual average temperatures over the years 1880 to 2009.png. January 2009.
4. Hannah Ritchie and Max Roser, “CO₂ and Greenhouse Gas Emissions,” Our World in Data, last revised December 2019. See Creative Commons license link https://creativecommons.org/licenses/by/3.0/au/.
5. David Roberts, “Scientists have gotten predictions of global warming right since the 1970s,” Vox, December 4, 2019, https://www.vox.com/energy-and-environment/2019/12/4/20991315/climate-change-prediction-models-accurate.

BLOG TOPICS: I write content (in-depth) blogs about a mix of topics: Health and Hiking, Inspiration and Hope, Science and Energy.
The Gray Nomad ….. Looking at the data.
The angel of the Lord came and sat down under the oak tree…where Gideon was threshing wheat in a winepress to keep it from the Midianites. When the angel of the Lord appeared to Gideon, he said, “The Lord is with you, mighty warrior.”
[Book of Judges, chapter 6.]

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3 years ago

Frightening yet all too real, Ian! Thank You for taking this on & enlightening us “lay people”! I understand Global Warming & climate change in a general sense & support climate Change scientists. I do what I can by recycling, use of passive solar-in my home & conservation strategies. To think any child born in 2020 will experience this sober possibility in 2100. Looking forward to part 2. Please give me your thoughts on Paris Accord as well.

Gray Nomad
Gray Nomad
3 years ago
Reply to  Patti

Hi Patti. I’m glad you are into resource conservation in the home, as this could make a huge difference if a large number of people started doing this. Quick comment on the Paris Accord. In my new “Shale” book I discuss the “production gap” where oil and gas companies (burning of fossil fuels provides 65% of CO2) are way behind in trying to reach the Paris goal of keeping global temperature rise to less than 2 degrees C by the year 2100.

3 years ago

Thanks again for another interesting and informative blog post. I hope we have the political, individual, national and international will to overcome our current appetite for fossil fuels and energy consumption. Our current political and civil atmosphere seems opposed to major changes.

Gray Nomad
Gray Nomad
3 years ago
Reply to  DonM

Having the will to make changes starts with understanding the science and its predictions, which the above graphs try to show. As you said, its fossil fuels and energy consumption, and the latter is critical too. I am reminded of my (not well off) parents teaching us kids to turn out the lights when we left the room.

Don C.
Don C.
3 years ago

After reading your blog prediction of the earth becoming hotter than its been for 400,000 years, I was reminded of a verse from the Second Book of Peter chapter 3 in the Bible: “Since everything around us is going to be destroyed like this… on that day, He will set the heavens on fire, and the elements will melt away in flames.”

Gray Nomad
Gray Nomad
3 years ago
Reply to  Don C.

Don, that is an interesting prediction from the Bible. I always thought that verse was referring to nuclear war, but you’ve raised an alternative interpretation.

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