As promised, Professor Mark Jacobson has answered Era's questions about climate change. What's more is that the professor took time to answer every single question forwarded!
If you submitted a question but cannot find it in the OP, it is likely due to one of the following reasons:
If none of the above apply to your question, you should find Professor Jacobson's response to your question in this post.
The questions will be divided into two categories: 'ESSENTIAL' and 'TANGENTIAL'. The 'essential' questions are questions that directly focus on the nature of climate change, addressing climate change, and/or its impact on life on Earth. The 'tangential' questions are questions that relate to climate change in a more indirect or roundabout way, or questions that focus on Professor Jacobson's specific methodologies as a scientist/researcher.
Also, you may notice that your question has been modified to a degree. This was done to ensure that questions were presented with clarity and coherent grammar, and/or to make sure that the question fully complied with the rules (e.g. some questions had multiple parts and had to be simplified per the interview rules).
In addition, since there were some posts in the submission thread that called Professor Jacobson's expertise into question, based on criticism from the professor's peers in the past, I have given the professor the opportunity to respond to some of these criticisms and he has done so, as you will find in the 'CRITICISMS' section of this post.Now with all of that out of the way, let's get on with the Q&A!
FORMAT: To improve readability, I've changed the format to match adj_noun 's style: User responses will be in bold, Professor Jacobson's responses will be italicized.
_________________________
ESSENTIAL QUESTIONS:
________________________
https://web.stanford.edu/group/efmh/jacobson/Articles/I/sad1109Jaco5p.indd.pdf
Although we have always believed a transition by 2030 is technically and economically possible, as proposed in the 2009 article, we believe that for social and political reasons, an 80% transition by 2030 and 100% no later than 2050 (and hopefully earlier, particularly in some sectors) is both achievable and more realistic. It is also a necessary timeline to return CO2 to 350 ppm by 2100
http://web.stanford.edu/group/efmh/jacobson/Articles/I/CountryGraphs/CO2ChangesWithWWS.pdf
and to avoid catastrophic damage from global warming and to eliminate the 7 million air pollution deaths per year from air pollution.
https://web.stanford.edu/group/efmh/jacobson/Articles/I/AirPollutionDeath.pdf
Based on our calculations, we think the Green New Deal (a 100% clean, renewable energy system) will reduce energy use by half thus reduce aggregate (absolute) energy costs by about half. By reducing air pollution and climate costs in the U.S., it will also reduce aggregate (absolute) social costs by 5/6 while creating many more jobs than lost.
https://cleantechnica.com/2019/03/09/why-the-green-new-deal-cuts-consumer-energy-costs-unemployment/
Adding carbon capture equipment to a coal or gas plant increases air pollution and mining of coal and gas and decreases CO2 only about 10% over 20 years, not 90%. This is before even accounting for leaks after the carbon is stored or used:
https://web.stanford.edu/group/efmh/jacobson/Articles/I/NatGasVsWWS&coal.pdf
The same poor result applies to synthetic direct air capture.
https://web.stanford.edu/group/efmh/jacobson/Articles/I/AirCaptureVsWWS.pdf
No, but sea levels will rise (up to a maximum of 80 m, which is how much sea level is stored in all the world's ice, mostly in the Antarctic).
Reforestation and reducing deforestation is the only effective means of drawing carbon out of the air, so yes that is a good idea and has additional benefits as well (e.g., vegetation absorbs air pollution as well).
https://web.stanford.edu/group/efmh/jacobson/Articles/I/NuclearVsWWS.pdf
https://web.stanford.edu/group/efmh/jacobson/Articles/I/AirCaptureVsWWS.pdf
2) Support policymakers who will put this solution into policy.
3) Make changes in your own life to meet this solution.
This is the best we can do.
1) Electrify everything and provide the electricity with clean, renewable energy.
2) Use electric heat pumps for air and water heating and air conditioning.
3) Use electric vehicles and hydrogen fuel cell vehicles, where the hydrogen is from electricity.
4) Electrify industry.
5) Reduce energy use.
2) Support policymakers who will put this solution into policy.
3) Make changes in your own life to meet this solution.
https://web.stanford.edu/group/efmh/jacobson/WWSBook/WWSBook.html
http://scpd.stanford.edu/search/publicCourseSearchDetails.do?method=load&courseId=87803904
https://web.stanford.edu/group/efmh/jacobson/Articles/I/GeoengineeringVsWWS.pdf
In addition, wind, solar; batteries for storage and electric cars; hydrogen fuel cell vehicles for heavy, long-distance transport; heat pumps (for air and water heating and air cooling) will grow substantially.
More damaging air pollution (since it gets worse with higher temperature).
More severe hurricanes and weather in general
More droughts/floods, especially coastal flooding.
Large shifts in agriculture
Greater heat-related deaths
More malaria, dengue fever
Greater coral reef loss/ocean acidification
Greater loss in biodiversity
More climate migration
https://climate.nasa.gov/vital-signs/global-temperature/
2) Use electric heat pumps for air and water heating and air conditioning.
3) Use electric vehicles and hydrogen fuel cell vehicles, where the hydrogen is from electricity.
4) Electrify industry.
5) Reduce energy use.
2) Add a more bike lanes to roads.
Some people will be exposed to more extreme heat, and this will kill or injure more people.
Others will be exposed to more severe weather.
Adjustments will be needed but I don' think the supply chain will be hampered too long since there will be financial incentives for everyone to secure the supply chain. Plus, there are many ways to produce different technologies and many different technologies that will be implemented.
___________________________
TANGENTIAL QUESTIONS:
___________________________
Yes, 4.6 billion years ago, the Earth was molten, which is why that time is called the Hadean eon.
And 100 million years ago, the Earth was ice free - but no people lived then. Now we have 7.5 billion, with most people living along coastlines.
http://web.stanford.edu/group/efmh/jacobson/Articles/I/CombiningRenew/PNASReplyClack.pdf
The problem was that PNAS published a paper with false information and did not correct it.
2) Two independent peer-reviewed articles have refuted the Clack et al. paper:
The first one,
https://www.sciencedirect.com/science/article/pii/S1364032118303897
concluded that Clack's and other critiques of 100% contain "factual errors, questionable assumption, important omissions, internal inconsistencies, exaggerations of limitations, and irrelevant arguments."
It goes on to state,
"Of particular concern is that PNAS published the Clack et al. article as a Research Report instead of a Letter to the Editor, although the article contained no original research -- it only criticised a genuine research paper with claims that generally don't stand up to examination."
and
"Our assessment is that Jacobson et al. have clearly refuted all but one of Clack et al. error claims. However, this is a minor 'error.'"
The second paper that debunks the Clack et al. paper and other critiques of 100% renewables is
https://www.sciencedirect.com/science/article/pii/S1364032118303307
which states, "As a result, we conclude that the 100% renewable energy scenarios proposed in the literature are not just feasible, but also viable."
3) The main conclusions of the Clack et al. paper were derived from their own errors, not from any error in our PNAS paper. For example, they pretended our Table 1 contained maximum values when they were fully informed and aware it contained average values. They used their own error to then claim we make modeling errors when it was their own mistake that produced this claim:
http://http://web.stanford.edu/group/efmh/jacobson/Articles/I/CombiningRenew/18-02-Correction.pdfobson/Articles/I/CombiningRenew/18-02-Correction.pdf
4) Three authors on the Clack paper (Sweeney, Weyant, Victor) are being paid by Trump to fight climate action
http://blogs2.law.columbia.edu/clim...nts/2018/20181015_docket-615-cv-1517_na-1.pdf
Two others (Caldeira, Qvist) wrote plans for the world to go all nuclear:
https://www.theguardian.com/environ...he-only-viable-path-forward-on-climate-change
https://www.nytimes.com/2019/02/05/...uture-joshua-s-goldstein-staffan-a-qvist.html
Others have research interests in technologies (e.g., natural gas, carbon capture) we do not include. These facts all speak to their motivation.
******
In sum, I and many others disagree with the premise of the question, that 100% renewables is not within reach. In fact, 8 countries are at 95-100% renewable electricity (not all energy) and 61 countries have commitments for 100%.
There are many ways to get to 100% WWS and storage (electricity, heat, cold, hydrogen storage) in all energy sectors at low cost.
http://web.stanford.edu/group/efmh/jacobson/Articles/I/CombiningRenew/WorldGridIntegration.pdf
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CRITICISMS:
_________________
Further, there was no error in our hydro calculations for the PNAS paper, only misrepresentation by the Clack et al. authors about what was done :
http://web.stanford.edu/group/efmh/jacobson/Articles/I/CombiningRenew/18-02-Correction.pdf
To the contrary, the idea of uprating hydro plants (increasing their nameplate capacity without increasing annual average power output) in order to help meet peaks in demand was a novel idea, which helped to earn the PNAS paper the Cozarelli Prize from PNAS. The U.S. Bureau of Reclamation
https://www.usbr.gov/power/edu/pamphlet.pdf
states that "uprating of existing hydro generator and turbine units is one of the most immediate, cost-effective, and environmentally acceptable means of developing additional electric power. Since 1978,..uprating added more than 1,600,000 kW at avg cost $69 per kW"
Whether hydro plants can be uprated to the level proposed in the paper is a social and political question, not a technical or even economic question See, for example, the calculated costs of such uprating here:
http://web.stanford.edu/group/efmh/jacobson/Articles/I/CombiningRenew/Clarification-PNAS15.pdf
In fact, it is much easier to do what we proposed than to implement the proposed schemes by two Clack authors (Caldeira and Qvist) who want to move the world almost entirely to nuclear power
https://www.theguardian.com/environ...he-only-viable-path-forward-on-climate-change
https://www.nytimes.com/2019/02/05/...uture-joshua-s-goldstein-staffan-a-qvist.html
or the scheme of Clack to convert the US entirely to HVDC transmission without any storage whatsoever.
https://www.nature.com/articles/nclimate2921
It was hypocritical for these authors, the only ones that claimed to perform work on a 21-author paper, to criticize a potential plan without criticizing their own even-more-difficult-to-implement plans.
There are at least 42 peer-reviewed papers supporting 100% renewables
http://web.stanford.edu/group/efmh/jacobson/Articles/I/CombiningRenew/100PercentPaperAbstracts.pdf
and independent peer-reviewed papers find 100% feasible.
https://www.sciencedirect.com/science/article/pii/S1364032118303897
https://www.sciencedirect.com/science/article/pii/S1364032118303307
so the claim that more realistic plans than 100% renewable is not substantiated.
https://www.usbr.gov/power/edu/pamphlet.pdf
states that "uprating of existing hydro generator and turbine units is one of the most immediate, cost-effective, and environmentally acceptable means of developing additional electric power. Since 1978,..uprating added more than 1,600,000 kW at avg cost $69 per kW"
Whether hydro plants can be uprated to the level proposed in the paper is a social and political question, not a technical or even economic question. In fact, it is much easier to do what we proposed than to implement the proposed schemes by two Clack authors (Caldeira and Qvist) who want to move the world almost entirely to nuclear power or the scheme of Clack to convert the US entirely to HVDC transmission without any storage whatsoever. It was hypocritical for these authors, the only ones that claimed to perform work on a 21-author paper, to criticize a potential plan without criticizing their own even-more-difficult-to-implement plans.
The 12 GW being referred to has nothing to do with uprating existing hydro plants. It has to do with powering non-powered dams.
https://web.stanford.edu/group/efmh/jacobson/Articles/I/NuclearVsWWS.pdf
______________________________________________
And that concludes the Q&A!
I would again like to thank Professor Jacobson for his time, as well as all of the users who submitted their questions. It is my hope that through this exchange, we all will have learned something valuable and do everything that we can to combat climate change in a way that causes the least amount of harm.
Thank you, everyone!
If you submitted a question but cannot find it in the OP, it is likely due to one of the following reasons:
- Your question did not comply with the rules that were established in this post
- Your question was too similar to a question that was already asked
- Your question was submitted after you already submitted a question
- Your question was submitted after the deadline
- Your question was deemed too inappropriate to be forwarded
If none of the above apply to your question, you should find Professor Jacobson's response to your question in this post.
The questions will be divided into two categories: 'ESSENTIAL' and 'TANGENTIAL'. The 'essential' questions are questions that directly focus on the nature of climate change, addressing climate change, and/or its impact on life on Earth. The 'tangential' questions are questions that relate to climate change in a more indirect or roundabout way, or questions that focus on Professor Jacobson's specific methodologies as a scientist/researcher.
Also, you may notice that your question has been modified to a degree. This was done to ensure that questions were presented with clarity and coherent grammar, and/or to make sure that the question fully complied with the rules (e.g. some questions had multiple parts and had to be simplified per the interview rules).
In addition, since there were some posts in the submission thread that called Professor Jacobson's expertise into question, based on criticism from the professor's peers in the past, I have given the professor the opportunity to respond to some of these criticisms and he has done so, as you will find in the 'CRITICISMS' section of this post.Now with all of that out of the way, let's get on with the Q&A!
FORMAT: To improve readability, I've changed the format to match adj_noun 's style: User responses will be in bold, Professor Jacobson's responses will be italicized.
_________________________
ESSENTIAL QUESTIONS:
________________________
The Green New Deal puts into policy what we have proposed since 2009, a 100% clean, renewable energy system for all energy sectors (electricity, transportation, building heating/cooling, industry).
https://web.stanford.edu/group/efmh/jacobson/Articles/I/sad1109Jaco5p.indd.pdf
Although we have always believed a transition by 2030 is technically and economically possible, as proposed in the 2009 article, we believe that for social and political reasons, an 80% transition by 2030 and 100% no later than 2050 (and hopefully earlier, particularly in some sectors) is both achievable and more realistic. It is also a necessary timeline to return CO2 to 350 ppm by 2100
http://web.stanford.edu/group/efmh/jacobson/Articles/I/CountryGraphs/CO2ChangesWithWWS.pdf
and to avoid catastrophic damage from global warming and to eliminate the 7 million air pollution deaths per year from air pollution.
https://web.stanford.edu/group/efmh/jacobson/Articles/I/AirPollutionDeath.pdf
Based on our calculations, we think the Green New Deal (a 100% clean, renewable energy system) will reduce energy use by half thus reduce aggregate (absolute) energy costs by about half. By reducing air pollution and climate costs in the U.S., it will also reduce aggregate (absolute) social costs by 5/6 while creating many more jobs than lost.
https://cleantechnica.com/2019/03/09/why-the-green-new-deal-cuts-consumer-energy-costs-unemployment/
The only effective carbon-absorbing technologies are natural air capture by trees and reducing deforestation.
Adding carbon capture equipment to a coal or gas plant increases air pollution and mining of coal and gas and decreases CO2 only about 10% over 20 years, not 90%. This is before even accounting for leaks after the carbon is stored or used:
https://web.stanford.edu/group/efmh/jacobson/Articles/I/NatGasVsWWS&coal.pdf
The same poor result applies to synthetic direct air capture.
https://web.stanford.edu/group/efmh/jacobson/Articles/I/AirCaptureVsWWS.pdf
I don't think they are. For example, a big effort has been made in the U.S. to phase out the most polluting coal plants.Our roadmaps capture all polluters, since our goal is to go to zero emissions for everything to address air pollution and climate.
No, but sea levels will rise (up to a maximum of 80 m, which is how much sea level is stored in all the world's ice, mostly in the Antarctic).
Reforestation and reducing deforestation is the only effective means of drawing carbon out of the air, so yes that is a good idea and has additional benefits as well (e.g., vegetation absorbs air pollution as well).
Aside from the Vogtle reactors being built, which will take 15-16 years to complete from the time of initial planning to operation, there are no other nuclear plants being planned for construction in the U.S., and many are slated for retirement. So, I see only a decrease in nuclear power output over the next 10 years in the U.S. Worldwide, nuclear output in 2018 was 6% lower than in 2006, so there has only been a decrease in the usefulness of nuclear power as a climate change tool in the past 13 years. Nuclear takes 10-19 years between planning and operation and costs 4-5 times that of new onshore wind or utility solar PV so is no longer competitive. It also has meltdown, weapons proliferation, waste, mining lung cancer, and CO2 emissions issues, so there are multiple issues that make it not an attractive method of energy production going forward. Small modular reactors cause many of the same problems. Please see more details of all these issues here:
https://web.stanford.edu/group/efmh/jacobson/Articles/I/NuclearVsWWS.pdf
Of the remaining candidates, Sen . Sanders has the most aggressive platform to combat climate change.
In general, individuals can help by electrifying their homes (eliminating the use of gas, gasoline, and fuel oil) as much as possible, improving energy efficiency of their home, and reducing energy use. Electrifying means using heat pumps for air and water heating and air conditioning instead of gas devices; using an electric induction cooktop instead of a gas stove or electric resistance stove; using electric vehicles instead of gasoline or diesel vehicles. Also, going to LED lights, more energy efficient appliances; weatherizing your home. Telecommuting more; flying less; driving less; biking more; walking more. Eat food with a lower carbon footprint. These are just some examples.
Provide incentives for alternatives to meat, which there are more and more of these days and/or tax beef consumption.
Direct air capture of CO2 just doesn't work effectively. Instead of reducing 90% of CO2, it reduces only about 10% over a 20 year time frame due to the high energy requirement of removal. As a result, it also increases air pollution and the mining for fossil fuels:
https://web.stanford.edu/group/efmh/jacobson/Articles/I/AirCaptureVsWWS.pdf
It would immediately help reduce the 78,000 air pollution deaths in the U.S. today and it would help reduce emissions of greenhouse gases proportionally to the reduction in global emissions it results in. However, given that 1 million is only 1/7,500th of the world's population and granted that the U.S emits more per capita than elsewhere, the impact would be much smaller than if the whole U.S. did the same.
Sea level has potential to rise up to 80 m, which is the amount of water stored in all ice worldwide. Hopefully, we can limit sea level rise before we get close to that limit.
Recycling helps, so the effort is useful, but its benefits have been modest in comparison with the total emissions from all sources that occur worldwide.
Eliminate combustion as a source of energy in favor of electrification and providing the electricity with clean, renewable energy.
History has shown that reducing emissions does not damage economic growth. To the contrary, countries that do not transition their energy now are the ones that will suffer greater economic disadvantage. Onshore wind and utility scale solar PV are the lowest forms of new electric power in the world today; electric cars save people money over their lifetimes. Heat pumps also save money.
Wind, solar; batteries for storage and electric cars; hydrogen fuel cell vehicles for heavy, long-distance transport; heat pumps (for air and water heating and air cooling).
Yes, because a lot of their operations can be cleaned up by electrifying agricultural equipment and processing machines and normal operations, and using electricity run on renewable energy is now less expensive than is using fossil energy for most applications.
I can't predict that.
1) Focus on the solution. Electrify all energy sectors and provide the electricity with clean, renewable energy and reduce all non-energy emissions. Use electric heat pumps for air and water heating and air conditioning. Use electric vehicles and hydrogen fuel cell vehicles, where the hydrogen is from electricity. Electrify industry. Reduce energy use.
2) Support policymakers who will put this solution into policy.
3) Make changes in your own life to meet this solution.
This is the best we can do.
The solution is simple:
1) Electrify everything and provide the electricity with clean, renewable energy.
2) Use electric heat pumps for air and water heating and air conditioning.
3) Use electric vehicles and hydrogen fuel cell vehicles, where the hydrogen is from electricity.
4) Electrify industry.
5) Reduce energy use.
I can't say exactly, but the Earth would be a lot warmer and climate damage would occur even more rapidly.
1) Focus on the solution. Electrify all energy sectors and provide the electricity with clean, renewable energy and reduce all non-energy emissions. Use electric heat pumps for air and water heating and air conditioning. Use electric vehicles and hydrogen fuel cell vehicles, where the hydrogen is from electricity. Electrify industry. Reduce energy use.
2) Support policymakers who will put this solution into policy.
3) Make changes in your own life to meet this solution.
Sea walls are enormously expensive and don't pay for themselves, so they are not practical on a large scale. We need to solve the problem to reduce the impact. Otherwise, we will need to adapt.
I teach about solutions and have a positive outlook because I know a solution is possible. I think this positive outlook can be seen in most every talk I give and in the new course I started teaching, "100% clean, renewable energy and storage for everything,"
https://web.stanford.edu/group/efmh/jacobson/WWSBook/WWSBook.html
http://scpd.stanford.edu/search/publicCourseSearchDetails.do?method=load&courseId=87803904
Focus on the solutions. A public opinion poll by Orsted found that only 66% of people believed climate change was a significant problem; however, 82% believed the world should transition to 100% clean, renewable energy. The reason is because renewable energy reduces costs, creates jobs, gives people pride in their country, and reduces health problems. Many people believe in clean, renewable energy without believing in climate change.
That, I can't say exactly, but I would guess that a diet of mostly fruit and vegetables and non-meat protein is best.
Geoengineering is not useful or helpful and, in fact, damaging:
https://web.stanford.edu/group/efmh/jacobson/Articles/I/GeoengineeringVsWWS.pdf
I can't say. I'm not sure.
Electricity storage with gravitational masses is one. Underground thermal energy storage is another.
In addition, wind, solar; batteries for storage and electric cars; hydrogen fuel cell vehicles for heavy, long-distance transport; heat pumps (for air and water heating and air cooling) will grow substantially.
Deforestation is a worldwide problem, particularly in the tropics. I can't compare the magnitudes off hand.
Yes, it will be noticeable but not nearly enough. In addition, it will eliminate 78,000 air pollution deaths per year in the U.S. from air pollution and millions of illnesses per year.
I'm not sure.
I can't answer that.
Higher sea levels.
More damaging air pollution (since it gets worse with higher temperature).
More severe hurricanes and weather in general
More droughts/floods, especially coastal flooding.
Large shifts in agriculture
Greater heat-related deaths
More malaria, dengue fever
Greater coral reef loss/ocean acidification
Greater loss in biodiversity
More climate migration
Louisiana, Florida, New York, California, Arizona, Nevada, Texas.
I can't say, but it is possible. Sounds like the trees are drier and the winds are stronger. Climate change does create drier vegetation in many places and more severe storms, particularly ocean storms (e.g., hurricanes, tropical storms).
NASA has up-to-date temperature data that are reliable:
https://climate.nasa.gov/vital-signs/global-temperature/
That's a personal decision that I won't wade into.
I don't know the answer to that.
Anywhere that is near the coast and less than 5 m above sea level, at least for the near term.
I don't know the answer to that off hand.
Coal is down to about 28% of US electricity production. I hope all electricity from coal is eliminated by no later than 2030.
No.
1) Electrify everything and provide the electricity with clean, renewable energy.
2) Use electric heat pumps for air and water heating and air conditioning.
3) Use electric vehicles and hydrogen fuel cell vehicles, where the hydrogen is from electricity.
4) Electrify industry.
5) Reduce energy use.
1) Ban natural gas and other fossil fuels during the new construction of buildings (as Berkeley has done).
2) Add a more bike lanes to roads.
A transition to 100% clean, renewable energy worldwide would reduce energy requirements 57% due to the efficiency of electricity over combustion and the elimination of energy to mine/transport/refine fossil fuels and uranium and due to modest end-use efficiency improvements. Thus, a transition would help to get us on a path to consuming less energy.
Sure. Venus is an example of the runaway greenhouse effect. However, chances are would stop emitting before that happened possibly due to running out of fossil fuels.
Through policies instituted by nations and by individual actions. Since transitioning to renewables reduces costs and creates jobs, countries should be motivated to transition.
Yes, that is the only useful method of removing carbon from the air (reforestation and reducing deforestation).
Hard to tell. I would need to know more. I don't know what the combustion emissions are and how much energy is needed to obtain the iron in the first place or how much is needed. In general, we want to eliminate combustion to eliminate air pollution in addition to eliminating carbon emissions.
Maybe. That is one way to try to educate people.
We should laser focus on the solutions and try to implement them as fast as possible. Then, we can say we did the best we possibly could.
Learn about the solutions and understand it is possible to solve the problem if we put our mind to it.
I know there is a solution if we eliminate 80% of emissions worldwide by 2030 and 100% no later than 2050 (hopefully earlier). We have the technologies to eliminate emissions and the costs are low today.
People in cities will be exposed to more air pollution, which will kill or injure more people.
Some people will be exposed to more extreme heat, and this will kill or injure more people.
Others will be exposed to more severe weather.
I expect the Arctic may be clear of ice within the next 10 years and that will cause positive feedbacks to accelerate warming faster. It is within our power to stop or slow this if we act quickly by implementing laws and personal actions to transition 80% of energy to clean, renewable energy worldwide by 2030 and 100% no later than 2050.
It all depends on cost, and I'm guessing this won't be cost competitive with wind/solar in most places.
Coastal erosion and flooding; more severe weather (including some additional hurricanes and more intense storms). Also hotter summers.
Adjustments will be needed but I don' think the supply chain will be hampered too long since there will be financial incentives for everyone to secure the supply chain. Plus, there are many ways to produce different technologies and many different technologies that will be implemented.
Yes, but the pace would be way too slow. For a solution to occur on the timescale that we need it, we need effective policies put in place as well as concerted personal actions.
Grow plants and trees.
___________________________
TANGENTIAL QUESTIONS:
___________________________
"The climate has been hot before."
Yes, 4.6 billion years ago, the Earth was molten, which is why that time is called the Hadean eon.
And 100 million years ago, the Earth was ice free - but no people lived then. Now we have 7.5 billion, with most people living along coastlines.
1) PNAS itself claimed it was trying to be neutral. PNAS published their paper and our detailed refutation of their claims, thus gave us the last word:
http://web.stanford.edu/group/efmh/jacobson/Articles/I/CombiningRenew/PNASReplyClack.pdf
The problem was that PNAS published a paper with false information and did not correct it.
2) Two independent peer-reviewed articles have refuted the Clack et al. paper:
The first one,
https://www.sciencedirect.com/science/article/pii/S1364032118303897
concluded that Clack's and other critiques of 100% contain "factual errors, questionable assumption, important omissions, internal inconsistencies, exaggerations of limitations, and irrelevant arguments."
It goes on to state,
"Of particular concern is that PNAS published the Clack et al. article as a Research Report instead of a Letter to the Editor, although the article contained no original research -- it only criticised a genuine research paper with claims that generally don't stand up to examination."
and
"Our assessment is that Jacobson et al. have clearly refuted all but one of Clack et al. error claims. However, this is a minor 'error.'"
The second paper that debunks the Clack et al. paper and other critiques of 100% renewables is
https://www.sciencedirect.com/science/article/pii/S1364032118303307
which states, "As a result, we conclude that the 100% renewable energy scenarios proposed in the literature are not just feasible, but also viable."
3) The main conclusions of the Clack et al. paper were derived from their own errors, not from any error in our PNAS paper. For example, they pretended our Table 1 contained maximum values when they were fully informed and aware it contained average values. They used their own error to then claim we make modeling errors when it was their own mistake that produced this claim:
http://http://web.stanford.edu/group/efmh/jacobson/Articles/I/CombiningRenew/18-02-Correction.pdfobson/Articles/I/CombiningRenew/18-02-Correction.pdf
4) Three authors on the Clack paper (Sweeney, Weyant, Victor) are being paid by Trump to fight climate action
http://blogs2.law.columbia.edu/clim...nts/2018/20181015_docket-615-cv-1517_na-1.pdf
Two others (Caldeira, Qvist) wrote plans for the world to go all nuclear:
https://www.theguardian.com/environ...he-only-viable-path-forward-on-climate-change
https://www.nytimes.com/2019/02/05/...uture-joshua-s-goldstein-staffan-a-qvist.html
Others have research interests in technologies (e.g., natural gas, carbon capture) we do not include. These facts all speak to their motivation.
******
In sum, I and many others disagree with the premise of the question, that 100% renewables is not within reach. In fact, 8 countries are at 95-100% renewable electricity (not all energy) and 61 countries have commitments for 100%.
There are many ways to get to 100% WWS and storage (electricity, heat, cold, hydrogen storage) in all energy sectors at low cost.
http://web.stanford.edu/group/efmh/jacobson/Articles/I/CombiningRenew/WorldGridIntegration.pdf
I haven't read it.
Not sure which process is being referred to.
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There has been no retraction whatsoever of the technical or economic feasibility of our 100% plan, either in PNAS or elsewhere.
Further, there was no error in our hydro calculations for the PNAS paper, only misrepresentation by the Clack et al. authors about what was done :
http://web.stanford.edu/group/efmh/jacobson/Articles/I/CombiningRenew/18-02-Correction.pdf
To the contrary, the idea of uprating hydro plants (increasing their nameplate capacity without increasing annual average power output) in order to help meet peaks in demand was a novel idea, which helped to earn the PNAS paper the Cozarelli Prize from PNAS. The U.S. Bureau of Reclamation
https://www.usbr.gov/power/edu/pamphlet.pdf
states that "uprating of existing hydro generator and turbine units is one of the most immediate, cost-effective, and environmentally acceptable means of developing additional electric power. Since 1978,..uprating added more than 1,600,000 kW at avg cost $69 per kW"
Whether hydro plants can be uprated to the level proposed in the paper is a social and political question, not a technical or even economic question See, for example, the calculated costs of such uprating here:
http://web.stanford.edu/group/efmh/jacobson/Articles/I/CombiningRenew/Clarification-PNAS15.pdf
In fact, it is much easier to do what we proposed than to implement the proposed schemes by two Clack authors (Caldeira and Qvist) who want to move the world almost entirely to nuclear power
https://www.theguardian.com/environ...he-only-viable-path-forward-on-climate-change
https://www.nytimes.com/2019/02/05/...uture-joshua-s-goldstein-staffan-a-qvist.html
or the scheme of Clack to convert the US entirely to HVDC transmission without any storage whatsoever.
https://www.nature.com/articles/nclimate2921
It was hypocritical for these authors, the only ones that claimed to perform work on a 21-author paper, to criticize a potential plan without criticizing their own even-more-difficult-to-implement plans.
There are at least 42 peer-reviewed papers supporting 100% renewables
http://web.stanford.edu/group/efmh/jacobson/Articles/I/CombiningRenew/100PercentPaperAbstracts.pdf
and independent peer-reviewed papers find 100% feasible.
https://www.sciencedirect.com/science/article/pii/S1364032118303897
https://www.sciencedirect.com/science/article/pii/S1364032118303307
so the claim that more realistic plans than 100% renewable is not substantiated.
The idea of uprating hydro plants (increasing their nameplate capacity without annual average power output) in order to help meet peaks in demand was a novel idea, which helped to earn the PNAS paper the Cozarelli Prize from PNAS. The U.S. Bureau of Reclamation
https://www.usbr.gov/power/edu/pamphlet.pdf
states that "uprating of existing hydro generator and turbine units is one of the most immediate, cost-effective, and environmentally acceptable means of developing additional electric power. Since 1978,..uprating added more than 1,600,000 kW at avg cost $69 per kW"
Whether hydro plants can be uprated to the level proposed in the paper is a social and political question, not a technical or even economic question. In fact, it is much easier to do what we proposed than to implement the proposed schemes by two Clack authors (Caldeira and Qvist) who want to move the world almost entirely to nuclear power or the scheme of Clack to convert the US entirely to HVDC transmission without any storage whatsoever. It was hypocritical for these authors, the only ones that claimed to perform work on a 21-author paper, to criticize a potential plan without criticizing their own even-more-difficult-to-implement plans.
The 12 GW being referred to has nothing to do with uprating existing hydro plants. It has to do with powering non-powered dams.
All nuclear plants ever built have had a planning-to-operation time of 10-19 years, so you're just illustrating why the Clack paper was flawed. The lower limit of nuclear war emission was zero, which the Clack authors failed to report. The higher emissions due to the time-lag between planning and operation of nuclear causes mortality, and this is a fact.
https://web.stanford.edu/group/efmh/jacobson/Articles/I/NuclearVsWWS.pdf
Aviation is already starting to be converted to hydrogen. The electricity analogy is misplaced since a WWS system converts all energy to electricity so electricity demand goes up by a factor of 2-3 but all energy goes down 50%.
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And that concludes the Q&A!
I would again like to thank Professor Jacobson for his time, as well as all of the users who submitted their questions. It is my hope that through this exchange, we all will have learned something valuable and do everything that we can to combat climate change in a way that causes the least amount of harm.
Thank you, everyone!
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