It all rather depends what you count as successful decarbonisation !  Personally I think your instinct is correct and a true removal of all use of methane and oil is likely impossible, probably by any date actually, and I am not optimistic about the potential for large scale carbon capture, except perhaps by planting trees and then burying them so they neither burn nor rot - I have yet to see a description of any closed cycle method that does not involve impractically vast volumes of lime or similar to scale to be useful at a global level.

However a substantial de-carbonisation from where we are now, to maybe 25- 30% perhaps (based on pidooma figures mind you ) should  be possible, and the use of biofuels and so on to tide us over the calm spots in the wind will help, as will long transmission lines from solar or wind facilities abroad.  Nuclear is probably part of any truly long term solution, but the grown up conversations about "do you want some nuclear  or to sit in the dark  for some weeks each year ?" are yet to be had in earnest.

none of this pessimism means it is not a target worth shooting for, just I expect us to miss somewhat.

Mike.

But we have the lowest levels of CO2 in the history of the planet. We should not decarbonise. 

What?  It's the highest it's been for 40000 years, at least.  Probably more, but it gets increasingly hard to tell beyond a certain point.

err, no we don't, firstly not according to recent history, (In the late 1700s, the air contained about 280 parts per million (ppm) of CO2. We crossed 300ppm just after world war 2, and  are now at 420 and something ppm and rising quite fast)

The last 100ppm of that rise has all been in my lifetime, which is very sobering,

climate.nasa.gov/.../

And also, perhaps more worryingly a high level according to the fossil record also. We are in territory uncharted since not long after the time of the dinosaurs, with one minor blip up to levels similar to today  since then, and that happened about 15 million years ago, took about 5 million years to recover and coincided with many extinctions.

Court high CO2 levels at your peril....

Mike.

That co2 graph shows no evidence of man made cause. Where's the down tick  when  covid stopped human activity.

https://www.climate.gov/media/14596

Yes, there was a wiggle around 2020.  But it was trivial compared with the massive increase in CO2 throughout the 20th century.

Jon Steward said:

That co2 graph shows no evidence of man made cause.

Unless I missed something, there haven't been massive numbers of volcanic eruptions that only started around 1870, or anything else that would explain it.  Can you think of any plausible natural explanation of why CO2 levels suddenly started rising so rapidly at a time that coincides with the industrial revolution?

There is a theory that covers that although I am not sure how it could be proven:

The world has been steadily warming since the little ice age as this plot of the Central England Temperature shows.

Increasing temperature increases the rate of respiration of plants. Who remembers the Nuffield science experiment using test tubes containing a standard sugar yeast mixture which were closed with a ballon? They were then put in water baths at different temperatures and the CO2 generation was judged by the inflation of the ballons.

Increasing temperatures will cause an increase in CO2 levels due to the increased respiration and growth of plant life. This will lag the temperature increase by a period of probably some years to allow for plant growth.

There is an opposite question, why did temperatures start rising in  the 1700s before the industrial revolution started?

well I don't know about you, but while covid may have stopped flights and restricted car travel,  I reckon the use of home heating and electricity consumption probably increased, and those readings are from Mona Loa - its a fairly smoothed rolling average of many months.

And of course the lockdowns were all over the place in that sort of timescale and far from simultaneous over the planet.  In the UK for example we had the first stay home orders in March, but then schools and shops re-opened in June with eat out to help out in August etc. And then we re-locked and did it all again in time for Christmas

https://www.instituteforgovernment.org.uk/data-visualisation/timeline-coronavirus-lockdowns

incredibly disruptive, incredibly expensive, but when seem in the context of an annual timeline, a short duration, and things were up and running for at least six months of the year.

I'm not too sure that we'd expect much of a dip, more of a wobble. - the total oil consumption figures do show not a lot of a dip either though the fuel prices went all over the place with panic buying and then overstocking.

For the UK the drop in fuel consumption in lockdown  is noticeable but not a total collapse by any means, and you have to see that against the trend that consumption of things like coal and gas use was already dropping.

total UK energy use dropped from 200 megatonnes of oil equivalents in 2018 to about 160-170 megatonnes in 2019 and 2020. to put that drop in perspective in 2018 it was already on the way down from about 220 in 2010-11 and higher still before that. And we don't have a pandemic now, and its still around the same levels, gently drifting down.

"lowest natural gas use since 2015" is not exactly a huge change either, as there was no pandemic in 2015, just a milder winter.

https://assets.publishing.service.gov.uk/media/622a228ed3bf7f1581a6eb22/DUKES_2021_Chapters_1_to_7.pdf for 2010- 2021 figures.

https://assets.publishing.service.gov.uk/media/66f420f1080bdf716392e8c1/Energy_Trends_September_2024.pdf for the more up to date stuff.

Mike.

Equally you could look at that graph and ask what changed in the UK in 1980 as before that it is a wobbly flat, after that it is a steady rise with a modest wobble superimposed. Maybe the dust and dirt of coal actually did us some favours by blacking out the peak of the sun ?
Mike.

We have warm and cold spells for all sorts of reasons.  There's a corresponding cold spell in the 1600's.  None of that explains the sudden massive spike in CO2 that started at the time of the industrial revolution.

Plants mostly absorb CO2 and let out O2.  So more plants should lead to falling CO2.  It's plants absorbing CO2 that explains how you can have a pot plant that's bigger than the pot it grew in - most of the plant is made from CO2.

Yeast isn't plants.  Yeast eats sugars and lets out CO2.  Pretty much the opposite of what plants do.

From the ice cores, CO2 wiggles from about 180 to 280 ppm for 800 000 years, with one spike to 300 ppm.  Then in the 20th century, it suddenly shot up through 300 ppm and is now 420 ppm and still rising.  There's nothing natural that's changed so fast.

But it corresponds entirely with the industrial revolution.

If humans are changing the atmosphere so rapidly, in a way that's never been seen before, then looking back at previous natural climate changes that took millennia to happen doesn't help.

Interestingly the rate of temperature rise between  1700 and 1725 is almost identical to the rise between 1980 and 2000. What are the mechanisms for two similar rises almost 300 years apart?

Interestingly the rate of temperature rise between  1700 and 1725 is almost identical to the rise between 1980 and 2000. What are the mechanisms for two similar rises almost 300 years apart?