Q&A of the Day – How Much Climate Change Can Be Attributed to People?
Each day I feature a listener question sent by one of these methods.
Email: brianmudd@iheartmedia.com
Social: @brianmuddradio
iHeartRadio: Use the Talkback feature – the microphone button on our station’s page in the iHeart app.
Today’s Entry: Hi Brian, I am in Europe this summer and I listen to your show whenever I can (7 hrs difference). We are being bombarded here daily as to the effects of climate change and the weather effects that according to local media, are causing unprecedented hot weather. I grew up in Greece and I remember that when I was in high school the summers were typically scorching. So nothing unusual to me. However, I am curious as to your fact-based take on climate change occurring because of the claim fossil fuel burn.
Something that has heuristically puzzled me is that given the stoppage in all industrial activity, worldwide during the covid period, I don’t remember experiencing any cooler than normal summers. So empirically, it causes me to be a skeptic on this topic. But I thought of turning to the data and facts guru, you.
Anyway, I appreciate your show very much and I appreciate your consideration of my question.
Bottom Line: First, thank you for continuing to listen, even while overseas! It’s been a few years since I was last in Europe, but I recall then that climate change conversation was all the rage – so I can imagine what it’s like right now as we have experienced some of the hottest weeks on record globally of late. And here at home it’s impossible to go a day without hearing and reading about water temps around Florida – which have recently touched 100 degrees in the lower keys. In wading into this conversation and analysis let’s first talk about climate change through the prism of what’s actually changed. The NOAA Climate Center maintains monitoring and data analysis which dates back to 1880. That provides us with a long-range view of what’s been and what’s happening. And the fact of the matter is that climate change is real as the climate has literally always been changing.
In the 142 years for which we have had reliable global temperature data from the National Centers for Environmental Information there’s been exactly one year that’s been “average”, or a year that wasn’t colder or hotter than usual and that was 1967. So given that the climate is always changing, which is easily reflected in changing global temperatures, here’s what we know. Measured against the average temperature of the past 142 years, we’ve had higher than average temperatures every year since 1978. 2016 was the hottest year on record, with the previous nine years all being within the top nine years for the highest global temperatures on record. And based on what we’ve seen thus far this year, it’s all but certain that this year will make it ten for ten with the potential for 2023 to end up being the hottest on record. So, the first clear matter of fact is that global temperatures have been consistently rising for over 45 years with the hottest years recorded in modern history all having occurred within the past decade. In terms of what that tends to feel like... The average global temperature is two degrees (Fahrenheit) warmer today than it was entering the 20th century. So yes, global warming is real. Climate change is real and that takes us to the next piece of the equation. How much impact have we and do we have in driving it?
Let’s start with the obvious. Earth has endured multiple mass extinction events with both periods of extreme heat and extreme cold long before we were around to have impacted the temperatures on the planet. To that end the EPA notes this as part of the documentation for “Natural Processes” that impact climate change:
Changes in the earth’s orbit and its axis of rotation have had a big impact on climate in the past. For example, the amount of summer sunshine on the Northern Hemisphere, which is affected by changes in the planet’s orbit, appears to be the primary cause of past cycles of ice ages, in which the earth has experienced long periods of cold temperatures (ice ages), as well as shorter interglacial periods (periods between ice ages) of relatively warmer temperatures.14 At the coldest part of the last glacial period (or ice age), the average global temperature was about 11°F colder than it is today. At the peak of the last interglacial period, however, the average global temperature was at most 2°F warmer than it is today.
With that information in hand, we know that throughout earth’s history there’s been a variance of 13 degrees attributed to astronomy. That said, there’s been no recorded change in our orbit or axis rotation documented over the past 142 years so that’s not an apparent factor here. Obviously, we haven’t had the impact of an asteroid, or extraordinary volcanic activity during this time either. Another natural factor which can impact global temperatures is solar activity, or essentially how bright and how hot the sun’s output is. There likewise has been no monitored change in recent decades. As we continue to factor in what can and will impact temperatures that takes us to gases. That’s where you have the big three that you so often hear about that are both naturally occurring and also produced through human activities. Those three are carbon dioxide, methane and nitrous oxide. There have been significant changes in the levels of those gases over time.
Detectable levels of all three gases, which can impact global temperatures, were essentially static from 1 A.D. until the start of the industrial revolution. Since that time, we’ve seen significant increases in the monitored levels of each. Here’s the increase in the gases today compared to pre-industrial times:
- Carbon Dioxide: 40% increase
- Methane: 250% increase
- Nitrous oxide: 20% increase
The carbon dioxide increases are attributable to deforestation and the burning of natural resources (coal, gas, oil). The methane increases are attributable to the production and distribution of natural resources (coal, gas, oil) in addition agricultural production and the decomposition of waste in landfills. The increase in nitrous oxide is attributable to the production and use of fertilizers.
So, when you lay all of the knowns and the facts together, we see that temperatures are about 2 degrees warmer than they used to be and that there are no natural factors which have changed significantly enough to account for that increase. At the same time, we have a spike in gases attributable to human activity that coincides with increases in temperatures. The scientific odds of the increase in temperatures being attributed mostly to human activities are currently greater than 95%. I understand the skepticism. As a conservative conservationist I’m as frustrated as anyone when these issues are politicized which seemingly is just about all of the time these days. That said, as always there are two sides to stories and one side to facts. These are the facts.