Climate Protection: Avoid furnace regrets

Nick Maxwell

I’ve been talking with folks about carbon dioxide and global overheating. Several times, people have heard the news and said, “Oh shoot! I just replaced my gas furnace.” I wish I could head off these kinds of heating mistakes.

Here is what I’ve been sharing:

Eight hundred thousand years ago, there were about 1.5 trillion tons of carbon dioxide in the air around the globe. The air was about .019% carbon dioxide. (If we were talking about alcohol molecules in someone’s bloodstream, “.019%” is the same as “a BAC of .019”.) At that time, the stone age had been going on for over two million years.

In the following 14,000 years, the carbon dioxide levels rose to .026%. Carbon dioxide levels then fell to .017% and we had an ice age. During an ice age, places like Canada are covered with miles of ice and people survive further South. A place like what is now Mexico does not get covered in glaciers.

About 750 thousand years ago, carbon dioxide rose again, temperatures rose, and the glaciers receded. About 700 thousand years ago, carbon dioxide started falling again, temperatures fell, and another ice age started.

This 100,000-year cycle of rising and falling carbon dioxide continued for the next 700,000 years. Throughout that time, our ancestors survived and sometimes thrived. About 400,000 years ago people started tying sharpened rocks onto shafts, creating the first spears.
All our history and a lot of the pre-history we know happened in the last 100,000 years. About 70,000 years ago, someone invented the bow and arrow. About 40,000 years ago, artists created cave paintings. The earliest settlements found in the Pacific Northwest are from 13,000 years ago. Farming took off about 10,000 years ago, and writing about 3,000 years ago.In 1800, James Watt invented a coal-fired steam engine that could run factories, and launched the coal industry. In 1870, John D. Rockefeller started the Standard Oil corporation, launching the oil industry. The natural gas industry started by 1940.

These three — coal, oil, and natural gas — are the major fossil fuels. All fossil fuels are mostly carbon and hydrogen. When someone burns them, the carbon atoms bond with oxygen to create carbon dioxide — the same stuff that stayed between .017% and .030% from 800,000 BCE to 1900.

There is a historical record of how much fossil fuel was burned. Almost all coal, oil, and gas burned from 1750 to the present was purchased. Taxes were collected and tax records were kept. It is just a task of chemistry and math to turn the history of fossil fuel taxes into a record how much carbon dioxide was released.

From 1750 to 2023, humans burned enough fossil fuel to release about 1.8 trillion tons of carbon dioxide. Back in 1750, there were about 2.2 trillion tons of carbon dioxide in the air. We have added another 1.8 trillion. About half of that carbon dioxide flew into the air and will stay there for centuries.

From 800,000 BCE to 1900, carbon dioxide levels stayed between .017% and .030%. Now it is up to .042%.

This history of carbon dioxide was created by scientists finding bubbles of ancient air and measuring how much they heat up with infrared (heat) radiation. From measurements of how much air heats up, scientists can calculate how much carbon dioxide the air contains. Infrared radiation rises from the surface of earth. This carbon dioxide history is a history of how much air was heated around the globe. We now have more carbon dioxide and that means hotter air.

Hotter air changes the weather. Hurricanes are grown by energy from the oceans. More heat is more ocean energy and we end up with faster hurricanes in new places with taller storm surges. Hot air absorbs more water. Hot air means longer and hotter droughts and more water in the sky to fall down when it rains, creating more flooding.

When I tell people about this, they sometimes get clarifications: “Natural gas is a fossil fuel?” “Yes.” “When I burn natural gas in my home furnace, I’m adding carbon dioxide into the air?” “Yes.”

A heat pump

“Oh shoot. I just replaced my gas furnace.”

Yes: “Oh shoot.” If your old gas furnace has worn out, you could get a heat pump. At that point, the heat pump is just an additional cost over what you would pay for a replacement furnace. If you just replaced your furnace, and now you replace your brand new furnace with a heat pump, whatever you spent on the furnace was wasted.

To avoid the risk of regrets later, if you are replacing a furnace, consider a heat pump.

What about…

Last month, I started this What-About section for odds and ends.

Environmental protection of electric vehicles

On average, American gasoline-powered vehicles get about 21 miles per gallon. A barrel of oil contains 135 kilos of oil and can be refined into 20 gallons of gasoline. An electric vehicle is expected to last about 300,000 miles. To drive a gasoline car 300,000 miles would require extracting 96,000 kilos of oil. That’s a lot of oil and there are a lot of gas vehicles, which is why the ecological devastation of oil extraction and transportation is so large. That is why we had the Exxon Valdez and Deepwater Horizon events.

Manufacturing an electric vehicle requires over a hundred more kilos of minerals than a gas car. The 96,000 kilos of oil that go into a gas vehicle swamp the difference in minerals. And the minerals that go into an electric vehicle can be recycled. The oil that goes into a gas-vehicle cannot. As electric vehicles get fully established, their ecological footprint will be smaller than gas vehicles.
If you have doubts about recycling, think about catalytic converters. The American recycling program for catalytic converters is running so well, people will come to your home to recycle your catalytic converter before you even ask them.


Washington State releases 100 million tons of greenhouse gases each year. That is 0.2% of the 50 billion tons of greenhouse gases that are released each year globally.

The government of Montana made an argument about this in a recent court case: the state government argued that Montana released about .1% of global greenhouse gases. They asked how Montana could be held responsible for stopping global overheating. The judge did not buy it.

Here is what is going on: Let’s say you belong to an organization that has 1,000 members. You are .1% of the organization. Your dues are only .1% of the funding for the organization. If you think like the Montana State government, you won’t pay your dues, because your dues are such a small part of the budget. If you did that, either you’re a freeloader when other people pitch in, or everyone else is like you, and the organization dies.

The way I was taught about this as a kid was my mom asking, “What if everyone tossed their gum wrapper on the ground?” Even though my gum wrapper would not by itself have worsened the neighborhood, I carried my gum wrapper home.

— Story, photos and graphics by Nick Maxwell

Nick Maxwell is a Climate Reality seminar leader in Edmonds, a Rewiring America local leader, and a climate protection educator at Climate Protection Northwest.


  1. Love hearing Nick’s telling of the Earth’s history! Some climate news days are totally overwhelming…so I picture our beautiful planet in the UNIVERSE and then I exhale and find calm…realizing how tiny our earth home really is in the bigger picture. In regard to the homes in which we reside, heat pumps are wonderful heaters/coolers! I wish every home had 1 (or more if you’re really big!) Still working toward the EV ownership.

    1. Thank you! I’m still working toward EV ownership too. We have a plug-in hybrid. It has a gas motor that runs a generator. In the summer, it takes us 34 miles on electricity from an outlet — 24 miles in the winter. For a lot of trips, that takes care of us, but not all. We buy gas about once a year. Our next car will be all electric and that may take years. I have been excited to see the used electric market grow.

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