checking in on the research
Dec. 11th, 2018 09:22 am![[personal profile]](https://www.dreamwidth.org/img/silk/identity/user.png){kind=small}
ljgeoffI used to post about this stuff a lot. Now I just check in on it every once in a while. Here's a paragraph from a 2018 meta analysis that caught my attention:
"What is known about the expected impacts under various warming levels (the damage function)? Moore et al (2017a) find that in a low warming scenario the global response yield, with CO2 fertilization and adaptation, is positive, and becomes negative in the 2 ◦C to 3 ◦C range. Without CO2 fertilization impacts are always negative. They also use the GTAP economic model to assess the impacts on welfare and derive an agriculture damage function, with confidence intervals. With CO2 fertilization, the welfare changes are negligible at 1 ◦C to 2 ◦C warming, becoming negative at 3 ◦C. Without CO2 fertilization there are substantial welfare losses at all warming levels." (my emphasis)
Juan-Carlos Ciscar et al 2018 Synthesis and Review: an inter-method comparison of climate change impacts on agriculture. Environ. Res. Lett. 13 070401 http://iopscience.iop.org/article/10.1088/1748-9326/aac7cb/pdf http://iopscience.iop.org/article/10.1088/1748-9326/aac7cb/meta
Global response yield becomes negative in the 2 ◦C to 3 ◦C range. If you add in the CO2 fertilization effect, the yield doesn't become negative until 3 ◦C.
From Climate Interactive Scoreboard:
485 ppm CO2 equivalent gives us about 2 ◦C of warming above pre-industrial levels.
At 855 ppm CO2 equivalent, we'll hit about 3.5 ◦C.
In 2018, the atmosphere reached its highest level in recorded history, at 410 parts per million. CO2 levels were about 280 parts per million before the Industrial Revolution in the late 1800s.
So what are we looking at?
From Wikipedia: https://commons.wikimedia.org/wiki/File:All_forcing_agents_CO2_equivalent_concentration.png#cite_ref-1 This file is made available under the Creative Commons CC0 1.0 Universal Public Domain Dedication. The person who associated a work with this deed has dedicated the work to the public domain by waiving all of his or her rights to the work worldwide under copyright law, including all related and neighboring rights, to the extent allowed by law. You can copy, modify, distribute and perform the work, even for commercial purposes, all without asking permission.
If we keep going as we are, we'll hit 485 ppm CO2 equivalent sometime in the 2030s, and 855 sometime in the 2060s. I expect that we'll hit 485 and then industry will slow down because people will begin to die. But even if we have a big collapse and stop burning fossil fuels, the earth will continue to warm due to the loss of albedo and increased methane pumping from the arctic circle until the CO2 gets taken up by the ocean and chemical weathering.
If we slow way down, more than we've promised that we will, we'll still hit 2◦C by the 2050s, and hit between 2.5◦C to 3◦C by 2100, so that gives us a possibility of a soft collapse with a world population of 25% - 50% what it is now. Soft collapse is the current best case scenario.
The green scenario on the chart is if the whole globe stops all anthropomorphic carbon emissions by something like 2020. Uh, no.
This does not take into effect the possibility of geoengineering (because, why not?) or carbon capture (sorry, I don't think we'll get this in time) or aliens or God stepping in and pulling our nuts from the fire.
In other words, nothing has changed. This is the same information that we had almost 10 years ago. Carry on.
"What is known about the expected impacts under various warming levels (the damage function)? Moore et al (2017a) find that in a low warming scenario the global response yield, with CO2 fertilization and adaptation, is positive, and becomes negative in the 2 ◦C to 3 ◦C range. Without CO2 fertilization impacts are always negative. They also use the GTAP economic model to assess the impacts on welfare and derive an agriculture damage function, with confidence intervals. With CO2 fertilization, the welfare changes are negligible at 1 ◦C to 2 ◦C warming, becoming negative at 3 ◦C. Without CO2 fertilization there are substantial welfare losses at all warming levels." (my emphasis)
Juan-Carlos Ciscar et al 2018 Synthesis and Review: an inter-method comparison of climate change impacts on agriculture. Environ. Res. Lett. 13 070401 http://iopscience.iop.org/article/10.1088/1748-9326/aac7cb/pdf http://iopscience.iop.org/article/10.1088/1748-9326/aac7cb/meta
Global response yield becomes negative in the 2 ◦C to 3 ◦C range. If you add in the CO2 fertilization effect, the yield doesn't become negative until 3 ◦C.
From Climate Interactive Scoreboard:
485 ppm CO2 equivalent gives us about 2 ◦C of warming above pre-industrial levels.
At 855 ppm CO2 equivalent, we'll hit about 3.5 ◦C.
In 2018, the atmosphere reached its highest level in recorded history, at 410 parts per million. CO2 levels were about 280 parts per million before the Industrial Revolution in the late 1800s.
So what are we looking at?
From Wikipedia: https://commons.wikimedia.org/wiki/File:All_forcing_agents_CO2_equivalent_concentration.png#cite_ref-1 This file is made available under the Creative Commons CC0 1.0 Universal Public Domain Dedication. The person who associated a work with this deed has dedicated the work to the public domain by waiving all of his or her rights to the work worldwide under copyright law, including all related and neighboring rights, to the extent allowed by law. You can copy, modify, distribute and perform the work, even for commercial purposes, all without asking permission.
If we keep going as we are, we'll hit 485 ppm CO2 equivalent sometime in the 2030s, and 855 sometime in the 2060s. I expect that we'll hit 485 and then industry will slow down because people will begin to die. But even if we have a big collapse and stop burning fossil fuels, the earth will continue to warm due to the loss of albedo and increased methane pumping from the arctic circle until the CO2 gets taken up by the ocean and chemical weathering.
If we slow way down, more than we've promised that we will, we'll still hit 2◦C by the 2050s, and hit between 2.5◦C to 3◦C by 2100, so that gives us a possibility of a soft collapse with a world population of 25% - 50% what it is now. Soft collapse is the current best case scenario.
The green scenario on the chart is if the whole globe stops all anthropomorphic carbon emissions by something like 2020. Uh, no.
This does not take into effect the possibility of geoengineering (because, why not?) or carbon capture (sorry, I don't think we'll get this in time) or aliens or God stepping in and pulling our nuts from the fire.
In other words, nothing has changed. This is the same information that we had almost 10 years ago. Carry on.
(no subject)
Date: 2018-12-30 05:35 am (UTC)