Cross Post this cdr thread, discussion on which covers Hansen calls for SRM
Andrew ---------- Forwarded message --------- From: Bruce Melton -- Austin, Texas <[email protected]> Date: Sat, 24 Dec 2022, 17:06 Subject: Re: [CDR] James Hansen's Recent Paper: Global Warming in the Pipeline To: Dan Miller <[email protected]> Cc: <[email protected]> Pretty amazing he is calling for SRM. One thing to remember about SRM when folks say it doesn't reduce emissions - it absolutely does reduce natural feedback emissions and accumulation because feedbacks increase with increasing temperature. Keith 2017 <https://keith.seas.harvard.edu/files/tkg/files/keith_et_al._-_2017_-_solar_geoengineering_reduces_atmospheric_carbon_bu.pdf> says reduced 100Gt C with RCP 8.5 at 2100. Still haven't jumped into Hansen's draft yet - annual end of year report is due and thawing neighbor's pipes out... you know, normal climate change things in Texas. It is supposed to be 70s in Austin by Wednesday. Yesterday 14 to 30. The Valentines Week 2021 Winter Storm Uri ice bomb with 144 hours below freezing and statewide grid failure smokes any cold event we have ever seen for duration, tho a few single clear calm nights have been a few degrees colder. This current event by absolute metrics was #3 behind 1989 but ahead of the old #3 in 2011, but this was the earliest ever for such an extreme event. Happy Holidays All! B Bruce Melton PE Director, Climate Change Now Initiative, 501c3 President, Melton Engineering Services Austin 8103 Kirkham Drive Austin, Texas 78736 (512)799-7998 ClimateDiscovery.org <https://climatediscovery.org/> ClimateChangePhoto.org <https://climatechangephoto.org/> MeltonEngineering.com <http://www.meltonengineering.com/> [email protected] <https://www.facebook.com/bruce.melton.395> [email protected] <https://www.instagram.com/bruce.c.melton/> The Band Climate Change <https://climatediscovery.org/climate-change-band/> Twitter - BruceCMelton1 <https://twitter.com/BruceCMelton1/> On 12/23/2022 8:15 PM, Dan Miller wrote: People will be shocked by Hansen’s next paper that will say the AMOC could shut down around 2050. That causes all kinds of havoc around the world, including lowering precipitation/agriculture productivity throughout the Northern Hemisphere and causes “multi-meter” (10+ feet) of sea level rise by 2100 (plus lots of other nasty surprises like “Storms of my grandchildren”). And this is a one-way switch for quite a while (centuries). No overshoot then come back. That’s why Hansen is calling for CDR & SRM. Dan On Dec 22, 2022, at 9:23 AM, Bruce Melton -- Austin, Texas <[email protected]> <[email protected]> wrote: Dan, Thank you for this pre-pub review and I eagerly await reading Hansen's usually voluminous findings. That we are increasing GHG's 20x faster than the PETM is extremely meaningful. I hope this makes it into the final version. I have spoken of Hansen et al's findings in establishing Sierra Club climate policy before, but let me repeat this story of how I convinced Sierra Club to lower their warming target from 350 ppm CO2 and 1.5 C to "350 and *less than 1 C*" as it may be helpful to some of you... Hansen's 2008 "Target Atmospheric CO2: Where should humanity aim?" was responsible for the Club (and many others) adopting a 350 ppm CO2 warming target. The basis of these 2008 findings is that 350 ppm CO2 was the safe level because this is the maximum concentration of CO2 in our atmosphere where our Earth systems are stable, or the boundaries where our current Earth systems evolved, and that levels of CO2 greater than 350 ppm risked irreversible Earth systems collapse and loss and or reversal of environmental services resulting in very large feedback emissions, where some time period of overshoot was allowable as long as we rapidly restored Earth's energy imbalance by lowering CO2 (and other GHGs) back to within evolutionary boundaries of Earth's systems. In 2017 Hansen et al published "Young people's burden: requirement of negative CO2 emissions" which for the first time modeled a 350 ppm CO2 world at 2100. Hansen's four scenarios with and without negative emissions to 2200 were: +2% annual emissions (business as usual BAU), constant CO2 concentration, -3% emissions (about net zero 2050) and -6% emissions (about net zero 2040). Results were 560 to 4,660 Gt CO2 removal plus net zero to achieve a temperature less than 1 C at 350 ppm CO2 in 2100 (1.5 C with BAU at 4,660 Gt). Sierra Club had adopted both 350 ppm and a 1.5 C target like many others. When "Young people's burden..." was published it became obvious to some (not the Club yet) that there was a conflict. By late 2019 when the policy team was wrapping up our work that was published in March 2020. A simple explanation to the policy team was all it took to get the Club to adopt a new target of 1 C, as the only possible safe future was one where Earth's temperature was within the evolutionary boundaries of its systems. Cheers, Bruce Bruce Melton PE Director, Climate Change Now Initiative, 501c3 President, Melton Engineering Services Austin 8103 Kirkham Drive Austin, Texas 78736 (512)799-7998 ClimateDiscovery.org <https://climatediscovery.org/> ClimateChangePhoto.org <https://climatechangephoto.org/> MeltonEngineering.com <http://www.meltonengineering.com/> [email protected] <https://www.facebook.com/bruce.melton.395> [email protected] <https://www.instagram.com/bruce.c.melton/> The Band Climate Change <https://climatediscovery.org/climate-change-band/> Twitter - BruceCMelton1 <https://twitter.com/BruceCMelton1/> On 12/21/2022 8:04 PM, Dan Miller wrote: James Hansen and 14 co-authors recently released a preprint (not yet peer reviewed) paper titled *“Global Warming in the Pipeline.”* This is an important paper that makes a number of key points, but the bottom line is we must act immediately to address the climate crisis. Hansen uses the framing *"human-made geoengineering of Earth’s climate must be rapidly phased out” *to call for emissions elimination, CDR and SRM. Hansen Newsletter Summary: https://mailchi.mp/caa/global-warming-in-the-pipeline?e=a29768a646 Full paper PDF: https://arxiv.org/pdf/2212.04474.pdf Here is a summary of some of the key points of this quite long (48 page) paper: 1. The Earth Climate Sensitivity (ECS) — the Earth’s *short-term* response to a CO2 doubling — is higher than previously assumed. Most scientists said it was ~3ºC, but Hansen et al now say it is 4ºC or more based on paleoclimate data. *This means there is more warming “in the pipeline” than previously assumed.* 2. While humans have increased atmospheric CO2 by 50% since the industrial revolution, the actual climate forcing from *all* the added greenhouse gases is now ~4W/m^2, which* is equivalent to a doubling of CO2* (i.e., CO2e (including all greenhouse gases, not just CO2) is about 560 ppm). 3. Part of the current warming has been hidden by human-made particulate air pollution (aerosols), mainly sulfur. When North America and Europe started to reduce emissions after the introduction of clean air acts in the 1970's, regional and global warming became more pronounced. In the past decades China and global shipping slashed sulfur emissions through cleaner fuels and sulfur filter systems ('scrubbers'). There are clear signals from ground, ocean and satellite based observations that *the rate of global warming has recently doubled*, which needs to be taken into account in risk assessments. 4. *Assuming* today’s forcing (4 W/m^2) stabilizes and human-made aerosols are eliminated, when all feedbacks — including “long-term” feedbacks — play out, *we are on track for about 10ºC warming and 6~7ºC if aerosols stay at today’s levels*. This is a “scenario” and we still control our future, though we are on track to *increase* climate forcing from today’s 4 W/m^2. 5. If greenhouse gas forcings keeps growing at the current rate, it could *match the level** PETM mass extinction <https://en.wikipedia.org/wiki/Paleocene%E2%80%93Eocene_Thermal_Maximum> within a century*. We are increasing climate forcing 20X faster than in the PETM so “long-term” feedbacks won’t take as long as in the paleo record (though some feedbacks will still be much longer than a human lifetime). 6. The paper concludes that we must: (a) implement a carbon fee and border duty (Fee and Dividend); (b) *"human-made geoengineering of Earth’s climate must be rapidly phased out,” *i.e., we must stop emitting greenhouse gases, remove CO2 from the atmosphere, and research and implement safe solar radiation management to counter the massive geoengineering experiment we are currently running; and (c) we must improve international cooperation to allow the developing world to grow using clean energy. 7. A companion paper will be coming out that addresses the* near-term shutdown of the AMOC and associated “multi-meter” sea level rise on a century timescale*. I did a Clubhouse podcast on this paper that you can listen to in your browser. Leon Simons, a co-author of the paper, was my guest. It’s a long podcast (2.5 hours)! <MKVLW5Wx.png> Hansen: We Are Committed to 7ºC Warming! - Climate Chat <https://www.clubhouse.com/room/MKVLW5Wx?utm_medium=ch_room_xerc&utm_campaign=JXq0RHi9uzX4m75doji2uw-507541> clubhouse.com <https://www.clubhouse.com/room/MKVLW5Wx?utm_medium=ch_room_xerc&utm_campaign=JXq0RHi9uzX4m75doji2uw-507541> <https://www.clubhouse.com/room/MKVLW5Wx?utm_medium=ch_room_xerc&utm_campaign=JXq0RHi9uzX4m75doji2uw-507541> Let me know if you have any questions. Best, Dan -- You received this message because you are subscribed to the Google Groups "Carbon Dioxide Removal" group. To unsubscribe from this group and stop receiving emails from it, send an email to [email protected]. To view this discussion on the web visit https://groups.google.com/d/msgid/CarbonDioxideRemoval/1A78A029-7B12-4975-89B3-98C8E249A423%40rodagroup.com <https://groups.google.com/d/msgid/CarbonDioxideRemoval/1A78A029-7B12-4975-89B3-98C8E249A423%40rodagroup.com?utm_medium=email&utm_source=footer> . -- You received this message because you are subscribed to the Google Groups "Carbon Dioxide Removal" group. To unsubscribe from this group and stop receiving emails from it, send an email to [email protected]. To view this discussion on the web visit https://groups.google.com/d/msgid/CarbonDioxideRemoval/83fad871-caa1-0370-ad2b-ce990f6789dd%40earthlink.net <https://groups.google.com/d/msgid/CarbonDioxideRemoval/83fad871-caa1-0370-ad2b-ce990f6789dd%40earthlink.net?utm_medium=email&utm_source=footer> . -- You received this message because you are subscribed to the Google Groups "Carbon Dioxide Removal" group. To unsubscribe from this group and stop receiving emails from it, send an email to [email protected]. To view this discussion on the web visit https://groups.google.com/d/msgid/CarbonDioxideRemoval/6de4ef67-2f97-8d40-320a-bb9c888d06b2%40earthlink.net <https://groups.google.com/d/msgid/CarbonDioxideRemoval/6de4ef67-2f97-8d40-320a-bb9c888d06b2%40earthlink.net?utm_medium=email&utm_source=footer> . -- You received this message because you are subscribed to the Google Groups "geoengineering" group. To unsubscribe from this group and stop receiving emails from it, send an email to [email protected]. To view this discussion on the web visit https://groups.google.com/d/msgid/geoengineering/CAJ3C-06svntdOg-Z-SVPvOm3-c6zS2RaoEgVjZ420QYpm9roeA%40mail.gmail.com.
