If the entire US residential sector were magically made emission free with everything else remaining the same, global output would be 37.24 billion metric tons instead - negligibly different and still the highest ever recorded.
I don't have figures for the EU available, but you figure it'd be a similar order of magnitude for residential. So if we just estimated it to be about the same, and made the entire EU zero-emission as well, we'd be at 36.93 billion metric tons, which is about where they were in 2018-2019, as well as 2021 due to the pandemic.
Now, you may say: ok, what about transportation and etc? In the US, it's about 28% of emissions from transportation, and of those, 57% are light duty vehicles (including most personal vehicles) - see https://www.epa.gov/greenvehicles/fast-facts-transportation-.... That was from 2022, but if we assume the percentages were about the same in 2023, they'd be about 767 million metric tons (=4.807 * .57 * .28).
So if we magically made all US residential AND personal vehicle emissions go to 0, global emissions would be 36.47 metric tons or about 2017-2018 levels.
If you again assume the EU is around the same as the US, and magically made all US/EU emissions go to 0, we'd have 35.394 metric tons of CO2, or about where levels were hovering in 2013-2016.
TL;DR: if you magically made the entire US residential and personal transport sectors 100% emissions free, global CO2 emissions would only go back to where they were in 2017-2018. If you throw the EU in as well we'd be in the 2013-2016 range.
True, residential emissions and personal transport might not make up the majority of emissions (though they make up a sizable amount). However, the effect of personal choices is not restricted to these two sectors. What things you buy and how often you buy new things an where they are built or grown, directly influences transportation and manufacturing of these goods. If we want to effectively combat climate change, we might need to consume less overall not only watch emissions at home or from personal transport.
For instance, in the US, residential made up 311 million of 4.807 billion total metric tons of CO2 output (https://www.eia.gov/environment/emissions/carbon/), which is about 6.5%.
Last year, emissions were 37.55 billion metric tons, which is the highest ever recorded (https://www.statista.com/statistics/276629/global-co2-emissi...).
If the entire US residential sector were magically made emission free with everything else remaining the same, global output would be 37.24 billion metric tons instead - negligibly different and still the highest ever recorded.
I don't have figures for the EU available, but you figure it'd be a similar order of magnitude for residential. So if we just estimated it to be about the same, and made the entire EU zero-emission as well, we'd be at 36.93 billion metric tons, which is about where they were in 2018-2019, as well as 2021 due to the pandemic.
Now, you may say: ok, what about transportation and etc? In the US, it's about 28% of emissions from transportation, and of those, 57% are light duty vehicles (including most personal vehicles) - see https://www.epa.gov/greenvehicles/fast-facts-transportation-.... That was from 2022, but if we assume the percentages were about the same in 2023, they'd be about 767 million metric tons (=4.807 * .57 * .28).
So if we magically made all US residential AND personal vehicle emissions go to 0, global emissions would be 36.47 metric tons or about 2017-2018 levels.
If you again assume the EU is around the same as the US, and magically made all US/EU emissions go to 0, we'd have 35.394 metric tons of CO2, or about where levels were hovering in 2013-2016.
TL;DR: if you magically made the entire US residential and personal transport sectors 100% emissions free, global CO2 emissions would only go back to where they were in 2017-2018. If you throw the EU in as well we'd be in the 2013-2016 range.