365 Days of Climate Awareness 360 – The Exxon Climate Fraud

On June 6, 1978—more than 44 years ago—an internal report entitled “The Greenhouse Effect” was delivered to the vice president the Exxon Research and Engineering Company. The report itself was the written version of the presentation by the author, J.F. Black, to the Exxon board the previous July (1977). It details then-current (1978) science on global warming, and is positively damning of the petroleum producer’s deliberate fraud in concealing, refusing to act on, and actively hindering action on global warming. Exxon’s internal report is the clearest example we have of a major oil producer knowingly putting profits above all consideration of global welfare.

A few choice quotes from the 1978 report. “Present [1978] thinking holds that man has a time window of five to ten years before the need for hard decisions regarding changes in energy strategies might become critical.” (P. 2) That is to say, between 1982 and 1987 governments and consumers should have been preparing to decarbonize the economy. Models, though primitive, were more optimistic, but not wildly different from our present understanding: “[w]hat is considered the best presently available climate model for treating the Greenhouse Effect predicts that a doubling of the CO₂ concentration in the atmosphere would produce a mean temperature increase of about 2ºC to 3ºC over most of the earth. The model also predicts that the temperature increase near the poles may be two to three times this value.” (P. 1. Mauna Loa, Hawaii CO₂ concentration annual mean: 1977, 335.41 ppm; 2021, 416.45 ppm) They even predicted Arctic amplification!

Mauna Loa atmospheric  CO₂ concentration record.

To be fair, consensus was only being built in the 1ate 1970’s, but the evidence was steadily accumulating: “[a]lthough carbon dioxide increase is predominantly attributed to fossil fuel combustion, most scientists agree that more research ls needed to definitely establish this relationship. The possibility that the increasing carbon dioxide in the atmosphere is due to a change in the natural balance has not yet been eliminated.” (P. 5) Even so, though opinions on global warming were not yet entirely firm, scientists had detected the major outlines: “...biologists have been claiming that deforestation and associated biogenic effects on the continents represent an important input of carbon dioxide to the atmosphere.” (P. 7) Most of the report is a copy of the visual presentation given to the Exxon board in July 1977.

Exxon’s response through the years has varied. In the early 80’s, the corporation focused its research efforts on climate modeling. By the late 80’s, when scientific consensus was becoming clear, Exxon’s focus shifted to its bottom line, and their public strategy was to question the science by, according to recent research, funding opposing viewpoints and pseudo-research organizations like the Heartland Institute. In the early 2000’s Exxon funded both studies which supported the concept of global warming, and which misrepresented existing findings and questioned it. In 2005, 39 out of 54 of the company’s environmental research grant awards went to denial-based reports.

At the same time, Exxon aggressively lobbied in Washington and elsewhere against global warming regulation, led by CEO Lee Raymond. Exxon might even have had a hand in the 2001 replacement of Robert Watson as chairperson of the Intergovernmental Panel on Climate Change (IPCC) with the more industry-friendly Rajendra K. Pachauri (though this also coincided with the beginning of the George W. Bush presidency). In a perfect example of the revolving door of corruption between government and industry, in 2005 Exxon hired Philip Cooney, recently disgraced ex-chief of the US Council on Environmental Quality (found to have been doctoring scientific reports to minimize evidence of warming), to an executive position. Prior to his time on the Council, Cooney had served as an oil industry lobbyist. From the oil industry to government, and then back to the oil industry.

In 2007, Exxon’s position began to soften, and in 2009 they publicly disavowed climate change denial efforts, but it was not until 2014 that the company explicitly acknowledged climate change as a threat to society. Since that time Exxon has endorsed a carbon tax as the best means of carbon regulation.

Tomorrow: introduction to Life Cycle Assessments (LCAs).

Be brave, be steadfast, and be well.

Exxon Report on Global Warming, June 6, 1978

Wikipedia - the Exxon climate change scandal

365 Days of Climate Awareness 359 – Cryptocurrency and global warming

Cryptocurrency is a digital form of money based in an encrypted (coded) data string stored across a distributed network of many computers. The distributed data string, or distributed ledger, is known as “blockchain”. The blockchain is a complete record of all buying and selling transactions performed on the currency, linked together into one single "chain" of data. Because it is encrypted and stored on a distributed peer-to-peer (i.e. no central, coordinating computer) network—two powerful layers of security—it is extremely difficult to steal or double-sell. Theoretically, cryptocurrency offers a secure form of money independent of government interference.

Properties of blockchain.

Number of publicly available cryptocurrencies, 2013-2021.

Blockchain was created in 2008 by Satoshi Nakamoto (a pseudonym: his or her identity is still unknown) as the ledger for Bitcoin, the first cryptocurrency, which was released in 2009. Blockchain--the encrypted ledger—was created specifically to prevent double sales of currency without requiring a central computer. Every transaction is added as a data unit to the existing blockchain, making it ever longer. To access your personal transactions, you need the encryption key. Without that key, you lose access to your segments of the blockchain, and therefore, to any currency you own there. Suffice to say your encryption key is absolutely critical to using cryptocurrency!

Number of transactions performed on select cryptocurrencies.

Recent price volatility of select cryptocurrencies.

Central to the concept of cryptocurrency, and the root of its climate impact, is “mining”. Crypto users employ their computers (nodes) to work on the blockchain, timestamping and “validating” existing transactions. The users receive payment in cryptocurrency for the transaction validations which their computers do. As the number of users has increased, the task of validating transactions has become more complex, and the rewards (fees) per validation have declined.

Market share of major cryptocurrencies.

As the fees for block validations have decreased, the number of users has increased and the energy consumption of cryptocurrencies has grown dramatically worldwide, surpassing the aggregate electricity demand of many countries. Because of the distributed, unregulated nature of cryptocurrencies, estimates of energy consumption vary widely. Generally speaking, there is much more uncertainty toward the high side of crypto-related energy estimates. This is because, as cryptocurrencies gain value (the theoretical value of the currency is not the same as the transaction fee), many smaller users with less efficient nodes begin mining, using much more energy. It is notable that none of the US’ recent “game changing” climate laws (the most recent, as of writing, still an unpassed bill) address cryptocurrencies.

Estimated energy consumption (2016-2021) of Bitcoin mining, along with electricity consumption of select countries (2021).

2019 electricity consumption.

Estimates of crypto-related CO₂ emissions are dire. One study estimated that 2020 emissions related to Bitcoin were 25.2 MtCO₂ (megatons of CO₂), the equivalent of 2.6-2.7 billion average homes around the world. Another study estimates that cryptomining in China alone could create 143 MtCO₂ emissions by 2024. The entirely decentralized nature of cryptocurrencies—a deliberate feature of their design—makes remediation of this energy consumption problem difficult. It also highlights the immediate need to increase our renewable energy capacity. As of now there is no globally coordinated effort to regulate cryptocurrency, meaning the problem is unlikely to change.

Tomorrow: EXXON’s climate fraud.

Be brave, be steadfast, and be well.

365 Days of Climate Awareness 358 – Innovation and Technology Development and Transfer

Technological development and innovation can be double-edged swords, depending on their application. The drive for more efficient and low- to no-carbon energy sources has provided undeniable progress in lightening society’s carbon footprint. However, as with the mixed benefits of computerizing industry and services: increased speed and efficiency can also lead to higher overall consumption as the market grows along with, or beyond, its greater speed and efficiency. Improved technology by itself is not sufficient to avert the climate crisis.

All illustrations from the IPCC 6th Assessment Report, Vol. 3, Chap. 16. Government funding for research and development in energy, 1974-2018, Organization for Economic Co-Operation and Development nations. 

Innovation is the application of existing technology or methods to novel uses. The war in Ukraine has shown the world a pretty stunning array of innovations the Ukrainians have used in their national defense, from repurposing grenades as bombs dropped from drones,
to a cloud-based app which directs artillery fire across an entire front. In more peaceful pursuits, photovoltaic (PV) roadways and roadside panels, used then for lighting, are others. The world is full of creative uses of existing technology. Development is the creation of new technology and methods (like ongoing work on hydrogen fusion).

It’s been observed that technological progress is limited in developing countries, because the means to promote and apply the progress are small or lacking. Where educational systems and infrastructure are inferior or nonexistent, the means and inspiration for technological progress is limited. For this reason sharing technology, from the developed to the developing world, is crucial. Many of the mitigations outlined in the AR6 report call for greater sustainability in the developing world, as it develops. This has no chance of occurring without the voluntary and widespread sharing of modern, cleaner and more efficient equipment, designs and methods. To use the very well-worn analogy, there is no need, and no time, to ask developing nations to re-invent the wheel.

Innovation objectives and mechanisms. 

To this end, intellectual property (IP) rights are sometimes considered helpful, sometimes harmful. Businesses use IP law to preserve trade secrets like improved technology and innovative concepts.  However, strong IP rights in developed countries provide companies with the incentive to continue developing new methods, secure within IP law to generate a profit. And this exposes another main challenge in confronting climate change: the drive for profit is at times completely opposed to the need to improve material conditions around the world, in places too poor to afford them. Bringing solar or wind generation to developing regions where coal and coke are used for fuel would be hugely expensive and require large external investments.

Social-technical transition. 

Many of the areas most urgently affected by global warming, such as tropical nations where sea level rise and extreme temperatures threaten large territories at once, lack the funding to improve their own technology or mitigate threats.  This is why we can meaningfully mitigate climate change only if we have robust international cooperation between governments. All other methods, while necessary, are insufficient. This brings us to the end of the month-plus survey of the IPCC’s Sixth Assessment Report. It wound up being about twice as many days as I’d planned to spend, but those days were thoroughly worthwhile. The IPCC report is very thorough and covered several areas, like buildings, urban development and technology sharing, which I omitted during the course of the year. So, now onward to other topics!

Tomorrow: cryptocurrency and global warming.

Be brave, be steadfast, and be well.

IPCC 6th Assessment Report, Vol. 3, Chap. 16

Organization for Economic Co-Operation and Development (OECD)

International Energy Agency (IEA), a branch of the OECD

365 Days of Climate Awareness 357 – International Cooperation

International cooperation on environmental issues has led to demonstrable results on the global scale. One of the best examples, and directly relevant to the issue of climate change, is the handling in the 1970’s and 80’s of acid rain, the product of sulfur dioxide (SO₂) emitted from smokestacks which made rain droplets acidic. This acidified water destroyed forests, killed fish populations and damaged buildings (particularly old and ancient) around the world. The 1979 Long-Range Transboundary Air-Pollution(LRTAP) addressed this and related problems, which states parties (including the United States and much of Europe) then remediated, dramatically reducing the problem.

All illustrations from the IPCC 6th Assessment Report, Vol. 3, Chap. 14. Framework of the 2015 Paris Agreement on climate change.  

Another issue from that time was ozone depletion due to chlorofluorocarbons (CFCs), which was addressed in the 1988 Vienna Conventionfor the Protection of the Ozone Layer. The treaty came into force only in 2009 but by that time the main actors had long since enacted laws eliminating manufacture of CFCs. The ozone hole in the Antarctic still exists and is monitored by NASA, but is no longer the growing threat it was a generation and a half ago. These are two urgent environmental problems which scientific monitoring, international cooperation and governmental action had direct hands in solving. Global warming can and should be different only in that public and private sectors must cooperate, because of the vastly greater scale of the climate change crisis.

Emissions cuts required by governmental action and cooperation for 1 . 5°C and 2 . 0°C global warming targets, respectively. 

Since the IPCC’s 2014 publication of its Fifth Assessment Report, the governments of the world have set up the 2015 Paris Agreement, which enjoins the parties (192 countries plus the European Union as a bloc) to set voluntary emissions targets with the goal of limiting global temperature rise to within 1.5°C/2.7°F of 1750 (pre-industrial) levels. The unfortunate truth is that the planet is currently on track for at least 2.0°C/3.6°F increase and, if nothing is done, more than 3.0°C/5.4°F. Any chance of lowering this, or at least preventing still worse levels of warming, will require concerted governmental action around the world.

The urgency has become so extreme, with many countries estimated to be badly lacking (or making no effort at all) that scientists and policy makers are now calling for the IPCC to research and publish a report on the potential extreme consequences of 3+°C/5.4+°F temperature rise, as a last-ditch effort to scare the collective public into realizing the scope and immediacy of the climate threat and make the needed efforts by governmental, societal and economic means to lower emissions.

Tomorrow: innovation and technology development and transfer

Be brave, be steadfast, and be well.

IPCC 6th Assessment Report, Vol. 3, Chap. 14

365 Days of Climate Awareness 356 – AR6 Vol 3, Chap. 13: National and Sub-National Policies and Institutions

Long-term, significant cuts in greenhouse gas (GHG) emissions cannot be achieved without governmental policy at the national, regional and even local levels, together. National policy is essential for implementing international treaties like the 2015 Paris Agreement, since all UN and other conventions assume the sovereignty of states parties (the legal term for treaty members, NOT the same as signatories. The US is a signatory, but not party, to the UN Law of the Sea, for example: the Senate has yet to ratify). Policy at the national and sub-national level provides the legal basis for action,
including frameworks for different groups and stakeholders to interact.

All illustrations from the IPCC 6th Assessment Report, Vol. 3, Chap. 13. (Top) Percentage of emissions covered by national climate policies, by region; (Bottom) Number of countries worldwide, and by region, which have enacted climate policies. [DEV = Developed countries; APC = Asia-Pacific developing countries; EEA = Eastern Europe and west-central Asia; AFR = Africa; LAM = Latin America and the Caribbean; MDE = Middle East]

Laws aid in climate change mitigation by creating incentives (hopefully powerful incentives) toward the reduction of carbon-intensive processes and activities, including across sectors (such as industry, energy and transportation, or energy and buildings, and of course, many more). Legal policies at different scales, from city or municipality level, to state or province level, to national level ensure comprehensive change. The corollary to this, unfortunately, is that large differences can grow between more proactive and less proactive governments, at all levels. This is painfully apparent at the national and sub-national levels. For example, in the US, climate change is a priority in many states, but completely ignored in others. 

Number of sub-national climate policies worldwide.

Sub-national policies are particularly important because, on the whole (obviously with differences between countries), regional and local authorities have jurisdiction over land use, a major aspect of greenhouse emissions. Policies to re-green territory and use it more sustainably are better executed at the state and local level.

Percentage of countries which have adopted some form of national climate policies, by sector.

At all levels, the media has critical power to help shape the dialogue, no less locally (even despite the gross centralization of modern media, and the death of many local news sources) than regionally and nationally. Biases toward or against certain topics—whether climate change or any other—can be blatant when news reports from different regions or countries are compared. All too often media outlets, especially in these days of fragmented news-as-entertainment, serve as a tool for bias confirmation. Digital, visual, audio and even print media can either retard or advance the cause for climate action, by explaining, minimizing or even ignoring the growing impacts of global warming on our daily lives.

Global fossil fuel subsidies, 2010-2020, as accounted by different organizations. [IMF = International Monetary Fund; IEA = International Energy Agency; OECD = Organization for Economic Co-operation and Development]

Cap-and-trade policies have been proven to be an effective means of reducing emissions, but have been largely stymied in the US. Fortunately, they are not the only tool. Efficiency mandates are also effective, but some of the best policies are forward-looking, subsidizing and prescribing new standards and links between sectors (energy and buildings, energy and transportation) to bring down emissions jointly in several different areas of society at once.

Number of Latin American and Caribbean countries which name adaptation (maroon) and mitigation (green) policies in their climate statements, 2018. NOTE this is not the count of actual policies, merely the mention of need for them in national climate studies.

A brief look forward. This is post #356, nearing the 365 goal in the blog’s title. I began writing these daily posts almost one year ago, when the first (at the time still somewhat rough) volume, The Physical Science Basis, of the Intergovernmental Panel on Climate Change (IPCC) Sixth Assessment Report was released. I wanted to spread awareness of the report, and help improve public knowledge of climate science in general, and global warming in particular. I’ve also seen, as we all have, the massive success of short-format Twitter in reshaping public discourse. So I decided on (usually) brief daily posts about limited topics, hoping, over the course of a year, to guide you through a reasonably complete survey of the climate as it is, has been, and is likely to be. I hope you’ve had as much fun reading as I have writing (though some days were more difficult than others)!

I plan two more posts on the AR6 Volume 3 (a few other chapters, like Financing, don’t interest me much, but please, read them if you like!) But I think the series will leak a little past the 365 count, as I have a few other topics I want to address, like the climate impact of cryptocurrency, the US Department of Defense’s posture on climate change, and a segment on Life Cycle Analyses—basically, the studies which answer the question, “how green is it anyway?” I’ll focus on offshore wind farms and electrical vehicles (EVs).

After that, I’m not sure I’ll be writing these posts every day. I’ve got some other projects lined up. But I might toss the ball to you guys. In grad school, my fellowship for two years involved assistant teaching science to 8^th graders, and one of my biggest successes (other than the time I dressed up as Marie Curie for the unit on radiation: one kid blurted out, “Hey Mr. Sutherland, where’d you get the coconuts?”) was the “Ask the Scientist” box, where students could anonymously ask questions about anything they wanted. So, in the spirit of that…if any of you folks have climate-related questions, I’ll take them, and do my best to answer. But I probably won’t be cranking out one per day. Anyhow…that’s enough for now! This is almost as long as my post on water.

Oh, and that reminds me: if you’re a relative newcomer, the entire 356 days (and onward) has been archived on my blog. The catalog is slightly clunky, and the formatting is…primitive. But it’s all there, if you want to look back. After a brief false start, I commenced with scientific basics and worked toward more complex climate issues. Happy (if you choose)reading!

Tomorrow: international cooperation.

Be brave, be steadfast, and be well.

IPCC 6th Assessment Report, Vol. 3, Chap. 13

365 Days of Climate Awareness 355: AR6 Vol. 3, Chap. 11: Industry

Since 2000, by all metrics, greenhouse gas (GHG) emissions due to industry have risen more quickly than from any other sector, accounting for 14.1 GtCO₂eq (gigatons of CO₂ equivalent) in 2019, 24% of the world total, second behind the energy sector (20 GtCO₂eq/34%). Achieving net-zero emissions from industrial sources is a huge but not impossible challenge. The main avenues for this are electrifying processes and switching to low- or zero-carbon energy sources, and finding low-carbon feedstocks.

 

All illustrations from the IPCC 6th Assessment Report, Vol. 3, Chap. 11. Aspects of decarbonizing industry.

Industrial greenhouse gas (GHG) emissions, 1900-2019. 

Among all types of physical stock bought and sold for industrial purposes, plastics have grown in use the most quickly since 1970. We depend on petroleum for more than 99% of feedstocks for plastic. Meanwhile we don’t recycle much and industrial processes emit large amounts of GHGs. This is one of the most difficult and essential areas for improvement in the entire range of mitigation scenarios.

Industrial feedstock demand, 1970-2019.

Industrial GHG emissions, 1970-2019, by world region.

It requires changing the frame of reference from small, incremental increases in efficiency, to a complete reimagining of some aspects of manufacturing (not unlike in the building sector, switching from efficiency to sufficiency). Scaling up newer, less GHG emissions-intensive manufacturing processes, and broadening the use of electricity (as we decarbonize the electricity sector) are within our capabilities now. Estimating the cost is difficult, however, because many aspects of pricing interact in, to use a mathematical term, nonlinear ways, where a single price adjustment will have several cascading effects, including on itself. While it’s easy to see the hesitancy of industrialists to retool, given this uncertainty, the growing certainty of climate-related disaster is changing the equation (to keep things math-y).

Industrial GHG emissions, 1970-2019.

The feedstock reliance on petroleum can be largely mitigated through use of biomass carbon (such as biomethane and methanol) and recycled materials. The question of who bears the costs for less emissions-intensive carbon sources is thornier. With sufficient innovation and scaling, costs for these alternate sources could be lowered from their currently high price.

Industrial GHG emissions, 1970-2019, by world region.

World demand growth for various materials, 1990-2019. 

However, the experience of the post-COVID environment has shown the world that large companies are all too willing to price goods oppressively. As with the difficulty of inducing behavioral change in people to consume and travel less, damping the profit motive in for-profit corporations is a bigger challenge than any technical issue. Bringing such a revolution about in industrial processes and pricing will require social and governmental action.

Material efficiency strategies.

Strategies for decarbonizing industry.

The use of concrete is frequently ignored in carbon budgets, because the materials for making it are cheap and easy to find. Concrete is overused because it is inexpensive and durable. Improved fabrication methods and more sparing use—only where concrete’s mechanical properties are needed—could reduce CO₂ emissions from this sector of industry 25-50% by 2050. But again, as in the case of alternate, more expensive feedstocks, the hurdle is asking developers to use more expensive, mechanically weaker alternatives where concrete is not necessary.

Toward low-carbon plastics.

GHG emissions for various scenarios and aspects of industry to 2100.  

A fair amount has been written on the geopolitical implications of renewable energy, with renewables-rich countries potentially becoming energy exporters (meanwhile, a prominent oil exporter like Saudi Arabia will remain important because inexpensive oil will remain economically necessary for several decades. But renewables have geo-economic impacts too, in terms of availability of renewable energy for industrial operations around the world. Developing countries, which can now simply import coke, coal or oil to fuel their growing manufacturing bases, would face a far more difficult tasks in building a parallel renewable energy industry alongside the manufacturing. Regional availability of low-carbon electricity is another huge challenge in decarbonizing industry.

Materials life cycles, mitigation and policies.

Tomorrow: national and sub-national policies and institutions.

Be brave, be steadfast, and be well.

IPCC 6th Assessment Report, Vol. 3, Chap. 11

365 Days of Climate Awareness 354 – AR6 Vol. 3, Chap. 10: Transportation

M

itigating greenhouse gas (GHG) emissions will require a thorough overhaul of our transportation systems, since they depend heavily on burning  petroleum-based fuels (especially gasoline, diesel, jet fuel and bunker oil). From 1990 to 2019, transportation sector GHG emissions rose from 5.0 to 8.7 GtCO₂eq, accounting for 23% of global emissions now. 70% of GHG emissions (6 Gt CO₂eq) come from road vehicles. 1% comes from rail, 11% from marine shipping and 12% from aviation, with shipping and aviation growing most rapidly.

All illustrations from the IPCC 6th Assessment Report, Vol. 3, Chap. 10. Global transport sector greenhouse gas (GHG) emission trends.  

Low carbon transportation-related energy pathways. 

The transportation sector is under scrutiny because of its reliance on fossil fuels. Gasoline, diesel, jet fuel and other liquids areeasily portable and have enough energy density (Megajoules per kilogram: gasoline, 44 MJ/kg; diesel, 45 MJ/kg; crude oil, 46 MJ/kg; natural gas, 55 MJ/kg) to sustain transport for hours in the air or across land, or for weeks at sea. Electrifying land transport and employing biofuels and hydrogen for shipping and air transport are obvious, though difficult, ways to mitigate emissions.

Commercial readiness of various low energy strategies.  

Transportation life cycle GHG emissions intensity. [ICEV = Internal Combustion Engine Vehicles; HEV = Hybrid Electric Vehicles; BEV = Battery Electric Vehicles; FCV = Fuel Cell Vehicles] 

Reconfiguring urban transport, particularly around public forms, which can be more easily electrified, could reduce urban GHG emissions related to transportation by 25%. Electric vehicles (EVs) have lower life cycle GHG emission than internal combustion engine (ICE) vehicles, when charged with low-carbon sources. As with other sectors, overlapping mitigation efforts will have mutual and cascading effects on global emissions. Turning to sustainable energy sources will improve the transportation sector as it electrifies.

Emissions intensity by vehicle type and mass. [ICEV = Internal Combustion Engine Vehicles; HEV = Hybrid Electric Vehicles; BEV = Battery Electric Vehicles] 

GHG emissions intensity, buses [ICEV = Internal Combustion Engine Vehicles; HEV = Hybrid Electric Vehicles; BEV = Battery Electric Vehicles; FCV = Fuel Cell Vehicles] 

Battery technology is improving and becoming less expensive, making not only light-duty personal transport, but heavy-duty truck transport increasingly viable (especially when, in heavy trucks, combined with hydrogen fuel). Along with the still-evolving battery technology, lack of infstructure to support EVs and hydrogen fuels is a main obstacle to their use.

GHG emissions intensity, medium-duty trucks [ICEV = Internal Combustion Engine Vehicles; HEV = Hybrid Electric Vehicles; BEV = Battery Electric Vehicles; FCV = Fuel Cell Vehicles]

Aviation emissions trends, 1950-2020. 

Without aggressive intervention, transport-related GHG emissions could increase from 16-50% by 2050, making it an urgent target for decarbonizing. This will require efforts at all levels, from individual consumer choices, to private enterprise developing more efficient technologies and governmental initiatives and research programs.

Trends and projected GHG emissions from the aviation sector to 2050. 

Projected emissions from the aviation sector to 2100. 

Tomorrow: industry.

Be brave, be steadfast, and be well.

Transportation-related GHG emissions by sector, region and scenario. 

IPCC 6th Assessment Report, Vol. 3, Chap. 10