Friday, November 02, 2018

Have CO2 Emissions Declined Under Trump?


Yesterday, or the day before, I can't remember, an NPR story that I can't find now, about plastics and, instead, making bottles from paper, said that US CO2 emissions have declined under Trump.

That's false.

Here are the 12-month increases in US CO2 emissions since Trump took office in Jan 2017:

The last six months have shown a clear month/12months-earlier increase in US CO2 emissions. At a rate of about half of economic growth.

Enough to matter? I don't know, how much matters?

As always, click the image for a clear picture, since Blogger renders these images for shit.

Currently US CO2 emissions data go up to July 2018 -- there's about a 4-month lag between now and the latest data -- but already it shows CO2 emissions increasing compared to 12-months before.

I don't know if this is due to policy changes, weather or what. According to my downloads -- which I do in an neverending effort to try to understand what the hell is going on -- the average temperature of USA48 was -1.07°F for March-May (meteorological spring) compared to the same period 1-year before, and +0.47°F for June-July, so far (2/3rds of meteorological summer, so far). Somewhat colder

There is actually a negative correlation between annual US CO2 emissions and the average annual USA48 temperature:

(Sorry, too much trouble to include Alaska and Hawaii. I'm sure they're used to being overlooked.)

So on the basis of temperature we would expect US CO2 emissions to be somewhat higher this year.

PS: That story, which was about replacing plastics with paper bottles (etc), was also sloppy with other parts of the science, I thought.

They noted that plastic was "made from fossil fuels." Yeah, sure. But that oil is sequestered in the plastic (though it might leak out over time. I'm not getting paid enough to figure out how much or how fast).

As well, making bottles of paper requires cutting down trees, and trees sequester carbon. How much carbon is lost after being sequestered in paper bottles? Like making plastic bottles, paper bottles require energy to manufacture. 

So what's the complete carbon budget here? Is it enough to matter, considering the US already emits about 5 Gt CO2? As I wrote, it's above my pay grade, which is $0 per whatever unit of time you wish to choose.

But I thought the NPR article slid over these issues much too slickly....


Layzej said...

This graph shows carbon dioxide emissions from energy consumption in the U.S continuing a long term trend towards lower emissions - even into 2017:

Possibly that is what NPR was referencing?

I'm curious about the negative correlation between CO2 emissions and temp. What is the time frame on that data? It looks like several decades worth of data?

David in Cal said...

Higher temperatures mean less fossil fuel used for heating, but more fossil fuel used of air conditioning. I don't know to what degree these offset.

From what I've read, the biggest reason for the reduction in CO2 emissions from energy consumption is the move toward using getting energy from natural gas.

Layzej said...

Interesting points DiC.

Layzej said...

"They noted that plastic was "made from fossil fuels." Yeah, sure. But that oil is sequestered in the plastic (though it might leak out over time. I'm not getting paid enough to figure out how much or how fast)."

This article suggests it could be sequestered effectively forever - rejected by bacteria and hidden from UV light:

...unless plastic eating bacteria evolve:

David in Cal said...

The fact that plastic is made from fossil fuels is one more reason to develop new sources of energy. Fossil fuels are enormous valuable materials. It's an incredible waste to just burn them up.