Mark Z. Jacobson

In June 2017, an article published in the PNAS critiqued Jacobson’s grid integration findings, alleging errors in methodology and assumptions. The PNAS published a response by Jacobson and co-authors disagreeing with Clack et al's premises and reaffirming the paper's conclusions. Clack et al then responded with details on specific errors in the PNAS response, claiming that each invalidated the results of the studies.

In 2017, Ken Caldeira and 20 other researchers published the largest focused critique of Jacobson's "100% Renewable world" paper. David Victor of the University of California, San Diego, a co-author of the critique of Jacobson’s model for a cheap "100% renewable world", was motivated to contribute to the paper "when policy makers started using this [Jacobson] paper for scientific support," when it was "obviously incorrect".

This 2017 critique resulted in Jacobson filing a lawsuit against the peer-reviewed scientific journal the Proceedings of the National Academy of Sciences and Christopher Clack as the principal author of the paper, demanding $10 million in damages for defamation. News reports and academics have criticized the lawsuit. Jacobson withdrew the lawsuit in 2018 after re-evaluating the time and cost associated with potential appeals, stating that when he filed the lawsuit, he expected a settlement.

Jacobson's 100% renewable world approach is supported by a 2016 publication by Mark Cooper, who has previously critiqued nuclear energy at the Vermont Law School, In 2016 Cooper published, a comparison of the 100% WWS roadmaps of Jacobson with deep decarbonization proposals that included nuclear power and fossil fuels with carbon capture. Cooper concluded that the 100% WWS pathway was the least cost and “Neither fossil fuels with CCS or nuclear power enters the least-cost, low-carbon portfolio.” This conclusion by Cooper is in stark contrast to a number of publications from 2011 to 2015, assessments by the Brookings Institution, Professor of Economics at MIT, Paul Joskow along with some independent scientists who have analyzed, with a different methodology, the various strategies proposed to get to a global zero or low carbon economy, by circa 2050. In these varied reports, the renewables-alone approach, has been claimed to cost "orders of magnitude" more and be more difficult to achieve than the more flexible energy paths, that have been assessed.

Loftus' assessment of some decarbonization plans, including Jacobson's, concluded in 2014-2015, that "more detailed analyses realistically addressing the key constraints", specifically relating to "the costs associated with integration of large amounts of variable generation" are needed. Jacobson's 100% renewable world, has raised concerns about integration/grid-stability and the issue of Brownouts damaging equipment, some solutions presented for these issues include an expansion on the reliance of energy storage systems. Jacobson counters these by citing 24 publications, primarily penned by the authors Breyer, Mathieson, Jacobson himself, and Diesendorf, that instead argue, that the "100% renewable world" is not simply theoretically possible but will work out cheaper than present electricity rates.

One of the most important fields of research that Jacobson has added to, with the aid of GATOR-GCMOM, is refining the range of values on exactly how much diffuse tropospheric black carbon, affects the climate. Something initially studied by his PhD adviser Richard Turco, when formulating the "nuclear winter" hypothesis of global cooling. The absorbed solar radiation gets converted to heat, which is re-emitted to the atmosphere. Under other circumstances the sunlight would potentially reflect back out into space, had the light struck a more reflective surface. Therefore as a whole, soot affects the planets albedo, a unit of reflectance. While the more familiar greenhouse gases warm the atmosphere by trapping thermal-infrared heat radiation that is emitted by the surface of the Earth, black carbon warms the atmosphere by absorbing sunlight and re-emitting that energy to the air around it as thermal-infrared heat. Jacobson and others drew from these models, that soot from diesel engines, coal-fired power plants and burning wood is a "major cause of the rapid melting of the Arctic's sea ice." Jacobson's refinement to the values on soot and his conclusion that black carbon may be the second leading cause of global warming in terms of radiative forcing was affirmed in the comprehensive review of Bond et al. (2013).

This analysis is controversial. Jacobson arrived at this conclusion of "25 times more carbon emissions than wind, per unit of energy generated" (68–180.1 g/kWh), by specifically expanding on some concepts that are highly contested. These include, though are not limited to, the suggestion that emissions associated with civil nuclear energy should, in the upper limit, include the risk of carbon emissions associated with the burning of cities resulting from a nuclear war aided by the expansion of nuclear energy and weapons to countries previously without them. An assumption that Jacobson's debating opponent similarly raised, during the Ted talk Does the world need nuclear energy? in 2010, with Jacobson heading the debate in the negative. Jacobson assumes, at the high end (180.1 g/kWh), that 4.1 g/kWh are due to some form of nuclear induced burning that will occur once every 30 years. At the low end, 0 g/kWh are due to nuclear induced burning. Responding to a commentary on his work in the Journal Environmental Science and Technology in 2013, Dr. James Hansen has characterized Jacobson's analysis on this topic of greenhouse gas emissions, as "lack(ing) credibility" and similarly regards Jacobson's other viewpoint of extra "opportunity-cost" emissions as "dubious". With the foundation of Hansen's incredulity being based on French experience, that decarbonized ~80% of the grid in 15 years, completed 56 reactors in the 15 year period, thus raising the fact that depending on the existence of established regulator certainty & political conditions, nuclear energy facilities have been accelerated through the licensing/planning phase and have therefore rapidly decarbonizated electric grids.

In response to Jacobson's paper on estimating the health effects of the Fukushima nuclear disaster, which projected approximately 180 "cancer-related morbidities" to eventually occur in the public, health physicist Professor Kathryn Higley of Oregon State University wrote in 2012, "The methods of the study were solid, and the estimates were reasonable, although there is still uncertainty around them. But given how much cancer already exists in the world, it would be very difficult to prove that anyone’s cancer was caused by the incident at Fukushima Daiichi. The World Health Organization estimates that 7.8 million people died worldwide in 2008, so 130 out of that number is quite small." She later said her remarks were "insufficiently nuanced". Burton Richter, tenured in Stanford with Jacobson, similarly stated in his critique, "It is a first rate job and uses sources of radioactivity measurements that have not been used before to get a very good picture of the geographic distribution of radiation, a very good idea". Richter also noted that "I also think there is too much editorializing about accident potential at Diablo Canyon which makes [Jacobson's] paper sound a bit like an anti-nuclear piece instead of the very good analysis that it is," and "It seems clear that considering only the electricity generated by the Fukushima plant, nuclear is much less damaging to health than coal and somewhat better that [sic] gas even after including the accident. If nuclear power had never been deployed in Japan the effects on the public would have [been] much worse."

Jacobson advocates a speedy transition to 100% renewable energy, to limit climate change. Jacobson co-founded the non-profit Solutions Project in 2011 along with Marco Krapels, Mark Ruffalo, and Josh Fox. The Solutions Project, a political advocacy group, combines presentations of science, business, and culture in an effort to influence energy policy switches to the "100% renewable world".

In 2009 Jacobson and Mark Delucchi published a paper in Scientific American proposing that the world should move to 100% renewable energy, namely wind, water, and solar power, in all energy sectors. In 2017, Christopher Clack, Ken Caldeira, and 19 other researchers challenged the findings of a followup 2015 paper published in the Proceedings of the National Academy of Sciences. In response, Jacobson filed, and later withdrew, a libel lawsuit against publisher PNAS, demanding retraction and $10 million in damages.

Jacobson has published papers about transitioning to 100% renewable energy systems, including the grid integration of renewable energy. He has concluded that wind, water, and solar (WWS) power can be scaled up in cost-effective ways to fulfill world energy demands in all energy sectors, In 2009 Jacobson and Mark A. Delucchi published "A Path to Sustainable Energy" in Scientific American. The article addressed several issues related to transitioning to 100% WWS, such as the energy required in a 100% electric world, the worldwide spatial footprint of wind farms, the availability of scarce materials needed to manufacture new systems and the ability to produce reliable energy on demand. Jacobson has updated and expanded this 2009 paper as the years progress, including a two-part article in the journal Energy Policy in 2010. Jacobson and his colleague estimated that 3.8 million wind turbines of 5-Megawatt (MW) size, 49,000 300-MW concentrated solar power plants, 40,000 300-MW solar PV power plants, 1.7 billion 3-kW rooftop PV systems, 5350 100-MW geothermal power plants, and some 270 new 1300-MW hydroelectric power plants would be needed. All of which would require approximately 1% of the world's land to be achieved.

Jacobson argues that if the United States wants to reduce global warming, air pollution and energy instability, it should invest only in the best energy options, and that nuclear power is not one of them. Like his PhD advisor Richard P. Turco, who notably coined the phrase "nuclear winter", Jacobson has taken a similar approach to calculating the hypothetical effects of nuclear wars on the climate but has further extended this into providing an analysis that intends to inform policy makers on which energy sources to support, as of 2009. Jacobson's analyses suggest that "nuclear power results in up to 25 times more carbon emissions per unit energy than wind energy".

British author and environmental activist Mark Lynas has criticized the paper's reliance on the disputed Linear no-threshold model (LNT) in its assessment of worldwide health effects. Lynas notes that in a 2007 recommendation, the International Commission on Radiological Protection had warned "the calculation of the number of cancer deaths based on collective effective doses from trivial individual doses [LNT] should be avoided." Due to its reliance on theory discredited by U.S. and international radiation experts, Lynas concluded Jacobsen et al's paper was "based on junk science" and was "worse than useless."

Because of the short atmospheric lifetime of black carbon, in 2002 Jacobson concluded that controlling soot is the fastest way to begin to control global warming and that it will likewise improve human health. However, he cautioned that controlling carbon dioxide, the leading cause of global warming, was imperative for stopping warming.

Jacobson began computer model development in 1990, when he started to build algorithms for what is now called GATOR-GCMOM (Gas, Aerosol, Transport, Radiation, General Circulation, Mesoscale, and Ocean Model). This model simulates air pollution, weather, and climate from the local to global scale. Zhang (2008, pp. 2901, 2902) calls Jacobson's model "the first fully-coupled online model in the history that accounts for all major feedbacks among major atmospheric processes based on first principles."

Mark Zachary Jacobson (born 1965) is a professor of civil and environmental engineering at Stanford University and director of its Atmosphere/Energy Program. Jacobson has developed computer models to study the effects of fossil fuel and biomass burning on air pollution, weather, and climate.