Climate Change

From: ICSF and Clintel         By: Roger Pielke Jr.         Date: October 27, 2021

A major concern regarding climate change is its potential future impact on food production, resulting from increasing temperatures and changes in precipitation. Experiments can demonstrate the effects of varying temperatures and precipitation on specific crops. However, climate models are not capable of accurately projecting regional temperature and precipitation changes which might result from climate change.

There is general agreement that the mild warming which has occurred during the current warm period has had a positive impact on farming in the US Midwest, extending growing seasons and reducing frost and freeze losses. Farm productivity has continually increased as the result of improved crop varieties, mechanized farming, the use of fertilizers and pesticides, and expanded irrigation. There is the expectation that this trend would continue until mid-century, but might then succumb to higher ambient temperatures.

The concern regarding food production beyond mid-century is a function of the projected increases in near-surface temperatures combined with projected changes in precipitation. The projected changes depend upon the model(s) chosen and the assumptions regarding climate sensitivity and feedbacks. Any projections are thus questionable, since there is no verified and validated climate model which has demonstrated predictive skill, the climate sensitivity to a doubling of atmospheric CO2 concentration is unknown and the future rate of increase of atmospheric CO2 concentration also unknown.

One major element of the expectation that farm productivity would continue to increase is the greening occurring over most of the globe, largely attributable to the increased atmospheric CO2 concentration, and the resulting improvement in the efficiency with which plants use available water in the enriched CO2 environment. Historical experience with greenhouse plant production demonstrates that plants continue to grow better at significantly higher CO2 concentrations than are anticipated as the result of continued anthropogenic emissions.

Another factor expected to mitigate the future effects of increasing temperatures is the fact that more than half of the temperature increases manifest as warmer nighttime temperatures, rather than higher daytime temperatures. The warmer nighttime temperatures are partially the result of increased irrigation and partially the result of more efficient plant water use, both of which increase ambient humidity, which slows night cooling.

Research conducted at Iowa State University demonstrated dramatic reductions in plant productivity under elevated temperature conditions. However, the high temperature used in the experiments was the same as the record high temperatures experienced during the Dust Bowl years of the 1930s, which were approximately 25°F warmer than the daytime temperatures during the warmest month on record, while the model projected temperature increase is expected to be approximately 7°F warmer than current temperatures by the IPCC.

The results of such studies are determined by the models, Resource Concentration Pathways, climate sensitivities and feedbacks selected to establish the experimental parameters. Fortunately, the models are “running hot” and Mother Nature is not comporting with the modeled environment. Recent research on climate sensitivity suggests that temperature increases will be far lower than projected and that cloud feedbacks are negative, which would work to moderate future temperature increases in the real climate.

From: Energy Central

By: Schalk Cloete

Date: October 27, 2021

The 10 Great Challenges Facing Variable Renewable Energy

Introduction

"Most green activists share a beautiful dream where cheap and abundant wind and solar energy mercilessly sweeps aside dirty fossil fuels. And the last decade brought plenty to cheer about.

Levelized costs of wind and solar are falling below fossil fuels in several world regions (IRENA).

"So, is the green dream finally coming true?

Unfortunately, not quite. After all these spectacular cost declines, variable renewable energy (VRE) generators still account for only about a quarter of primary energy growth (see the graph below), despite strong policy support. Why is that? Well, although more VRE deployment leads to technological learning, it also brings a host of challenges. These two conflicting forces will shape the VRE story going forward." ...

The 10 Great Challenges Facing Variable Renewable Energy

Refugees have fled from war, persecution, poverty, famine and pestilence over the ages. However, there is no documented record of refugees fleeing climate change, though a single resident of Tuvalu attempted to have himself accepted as a climate change refugee without success. MIT recently published an article reporting on the World Bank Groundswell Report which suggests that up to 216 million people might be required to migrate within their own countries as “climate shocks” occur.

“Climate change is a powerful driver of internal migration because of its impacts on people’s livelihoods and loss of livability in highly exposed locations. By 2050, Sub-Saharan Africa could see as many as 86 million internal climate migrants; East Asia and the Pacific, 49 million; South Asia, 40 million; North Africa, 19 million; Latin America, 17 million; and Eastern Europe and Central Asia, 5 million.”

These projections are all based on the unvalidated and unverified climate models in the CMIP5 ensemble of models and would be expected to be even worse using the CMIP6 ensemble of models, which project even more rapid and extreme temperature increases. Such studies typically employ the extreme Resource Concentration Pathway (RCP 8.5), which has frequently been described as the “business as usual” scenario, though it has more recently been identified as extremely unlikely by numerous researchers.

There is growing recognition that the climate models are “running hot”, projecting greater temperature anomaly increases than are observed in the real climate. The graph below, prepared by Dr. John Christy compares the model outputs with observations. Christy concludes that the hypothesis upon which the models were based has “failed”. This failure is the result of the use of high climate sensitivity to CO2, RCP 8.5 and the assumption of positive cloud feedback.

The historical observations strongly suggest that the likelihood of future “climate shocks”, particularly in the near term, is far lower than the models would project. This is consistent with recent research estimating lower climate sensitivity to CO2 and with satellite observations which suggest the cloud feedback is negative.

Note that, in the quote reproduced above from the World Band Groundswell Report, the authors state that “climate change IS a powerful driver of internal migration”, not that it might become such a driver. Yet climate change is not currently driving internal or external migration.

The primary issues of concern regarding migration are temperature increases and sea level rise. The report appears to ignore the fact that, in most regions, observed temperature increases are primarily warmer nighttime temperatures, not higher daytime temperatures. The report also appears to ignore the positive impacts of increased CO2 concentrations on global greening and the efficiency with which plants use available water.

The report also appears to ignore the fact that sea level has been rising at a consistent rate since the trough of the Little Ice Age. The rise of sea level from the Little Ice Age to the modern warm period is certainly climate change, but it is not likely attributable to increased atmospheric CO2 concentrations.

From: Climate Etc.

By: Judith Curry

Date: October 22, 2021

Challenges of the clean energy transition

"This morning I participated Conference on Energy and Decarbonization – A New Jersey Business Perspective. https://njbia.regfox.com/energy-summit.

UPDATE: full recording of the conference [here]

 New Jersey is a leader among U.S. states in aggressively tackling the transition to cleaner sources of energy (see the New Jersey Energy Master Plan).   So far, they have been doing a better job than California.   The near term challenges of the transition to clean energy are described in this article in the City Journal

New Jersey has a pretty good mix of electricity generation sources:  57.2% natural gas, 37.4% nuclear, 1.6% solar, 1.5% coal, 1.1% biomass, 0.9% non-biogenic waste, and 0.1% hydroelectric & wind.New Jersey’s renewable portfolio standard was updated in 2018 to require that 21% of electricity be from renewable sources by 2021, 35% by 2025, and 50% by 2030.

This Conference was a pretty interesting event.  Here is the agenda and list of speakers:" ...

Challenges of the clean energy transition

The Social Cost of Carbon (SCC) is an estimate of the present value of the societal cost of the emission of one ton of carbon dioxide. The SCC is estimated using Integrated Assessment Models, none of which has been validated and verified. The models are run using a range of estimated values for climate sensitivity, since the actual climate sensitivity to a doubling of atmospheric CO2 concentration is unknown. The present value of estimated future costs is calculated using a range of discount rates since the real discount rate is also unknown. As a result of the range of unknowns involved in the estimation process, SCCs ranging from -$13.36 - +$2386.91 per ton of CO2 (-$50 - +$8752 per ton of carbon) have been developed by various analysts.

There are currently no documented actual costs which have resulted from the increase in atmospheric CO2 concentrations from 270 ppmv to the current ~410 ppmv. There are also no documented financial benefits which have resulted from the higher atmospheric CO2 concentrations. However, the greening of the earth documented by NASA satellite observations is largely attributed to the increased CO2 concentrations, which have contributed both to more rapid plant growth and more efficient plant use of available water. Experimental results and long-term commercial greenhouse practices have documented to the effects of even higher CO2 concentrations on plant productivity.

A study by Dr. Indur M. Goklany identifies the various beneficial impacts of increased atmospheric CO2 concentrations and suggests that: ” It is very likely that the impact of rising carbon dioxide concentrations is currently net beneficial for both humanity and the biosphere generally. These benefits are real, whereas the costs of warming are uncertain. Halting the increase in carbon dioxide concentrations abruptly would deprive people and the planet of the benefits of carbon dioxide much sooner than they would reduce any costs of warming.”

Analysis of the modest recent warming, widely attributed to increased CO2 concentrations, demonstrates that approximately 60% of the warming has manifested as warmer low temperatures, rather than as higher maximum temperatures. This suggests that the projected adverse effects on those working in unconditioned environments would not be as severe as some have projected.

The uncertainties regarding the SCC resulting from the application of multiple unverified and unvalidated climate models using multiple Resource Consumption Pathways, multiple inconsistent Integrated Assessment Models and widely varying discount rates strongly suggests that the SCC is currently not fit for use as the basis for government climate policy. The possibility that the current SCC is low, or even negative, also strongly suggests that there is no “climate crisis’ and that there remains time to resolve the uncertainties in the science before committing to massively expensive, societally disruptive programs.

The societal benefits resulting from the various uses of fossil fuels are clear and compelling. The developing nations are well aware of those benefits and are clearly unwilling to sacrifice them.

From: Daily Reckoning

By: James Rickards

Date: October 12, 2021

“The Revenge of the Fossil Fuels”

"What have the climate alarmists been screaming about for the past 40 years or so? Their agenda is well-known. They want to close nuclear plants; shut down coal electric generators; eliminate natural gas and oil-fired electrical plants; and substitute wind, solar and hydropower in their place.

According to the fanatics, this substitution of renewable energy sources for so-called “fossil fuels” and uranium-powered plants would reduce CO2 emissions and save the planet from the existential threat of global warming.

Everything about this climate alarmist agenda is a fraud.

The evidence that the planet is warming is slight and the effect is likely temporary with global cooling in the forecast. The contribution of CO2 emissions to any global warming is not clear and is at best unsettled science and at worst another fraud.

Most importantly, global energy demand is growing much faster than renewables can come online, meaning that oil, natural gas, clean coal and nuclear energy will be needed whether renewables grow or not." ...

“The Revenge of the Fossil Fuels”

The US electric grid was built around a combination of baseload, load following and peaking generating plants. The US nuclear generating fleet has been used primarily for baseload service because the plants were reliable, and their design was not well suited to load following. The US coal generation fleet was used for both baseload and load following service. Oil and, later, natural gas simple cycle turbines were used for peaking service because they could be brought online quickly and could respond rapidly to changing demand. Hydroelectric generation, where available, was operated primarily as baseload generation because of its low cost. The introduction of natural gas combined cycle powerplants initially replaced simple cycle turbines because of their higher efficiency and operating flexibility. Later, they began to replace coal generators because of their higher efficiency and cleaner operation.

Concerns regarding climate change, the availability of various federal and state incentives, and the availability of lower cost wind and solar generators of improved design led to the introduction of these generating technologies into the US electric generating mix. However, both wind and solar differ in fundamentally important ways from conventional nuclear and fossil generation. Neither can be relied upon to be available when required and neither can be dispatched. They offer essentially “source of opportunity power”, available to be used when the wind blows and the sun shines. As wind and solar have entered the market, their “source of opportunity power” has been backed up by coal, natural gas and hydroelectric generation.

As the installed wind and solar generating capacity increases, the requirement for conventional backup also increases since the unavailability of wind and sun results in the loss of greater total generating capacity. This arrangement has worked reasonably well early in the intended transition to renewable generation. However, the expressed intent of the government is to eliminate the coal and natural gas generation which formed the backbone of the US generation fleet. This would also eliminate the ability to use fossil generation resources to provide backup power when the wind and solar generation resources are inadequate because of low wind conditions, cloudiness and darkness.

In the absence of dispatchable backup generation resources, the source of backup must transition to energy storage. Because of topography and environmentalist resistance to pumped hydro storage, the primary storage technology will likely be storage batteries. The storage battery capacity must be large enough to store all of the electric energy which would be expected to be needed during the longest period of low/no wind and solar availability which might be expected to occur. That also means that the wind and solar generating capacity must be large enough to serve almost all of the customer load when they are in operation, plus produce the additional electricity required to charge the storage batteries for use in periods of low/no wind and solar availability, and to recharge them afterwards.

Recent experience in the UK demonstrates that “wind droughts” can persist for weeks. In the current situation, the UK is able to draw power from the EU grid, supplied by nuclear, coal and natural gas generation. However, as the share of wind and solar generation increases and these conventional generating resources are eliminated, massive grid-scale storage facilities will be required to store the required electric energy and the capacity of wind and solar generation will be required to increase to charge the storage batteries. Prudence would also require the installation of both reserve generation and storage capacity to compensate for equipment maintenance and repair requirements.

The resolution of these issues is neither “blowin’ in the wind” nor basking in the sun. They must be resolved to avoid populations “freezing in the dark”.

From: Zero Hedge

By: Tyler Durden

Date: October 14, 2021

Here is The Hidden $150 Trillion Agenda Behind The "Crusade" Against Climate Change

"We now live in a world, where bizarro headlines such as the ones below, have become a daily if not hourly occurrence:

*TREASURY TO STUDY IMPACT OF CLIMATE ON HOUSEHOLDS, COMMUNITIES
*TREASURY LAUNCHES EFFORT ON CLIMATE-RELATED FINANCIAL RISKS
*BRAINARD: CLIMATE-SCENARIO ANALYSIS WILL HELP IDENTIFY RISKS
*BRAINARD: CLIMATE CHANGE COULD HAVE PROFOUND ECONOMIC EFFECTS
*MESTER: FED LOOKS AT CLIMATE CHANGE FROM VIEW OF RISKS TO BANKS
*FED IS TAKING THE RIGHT COURSE ON MONITORING CLIMATE CHANGE
*FED SHOULD CONSIDER CLIMATE-CHANGE RISK TO FINANCIAL SYSTEM

Now, in case someone is still confused, none of these institutions, and not a single of the erudite officials running them, give a rat's ass about the climate, about climate change risks, or about the fate of future generations of Americans (and certainly not about the rising water level sweeping away their massive waterfront mansions): if they did, total US debt and underfunded liabilities wouldn't be just shy of $160 trillion." ...

Here is The Hidden $150 Trillion Agenda Behind The "Crusade" Against Climate Change

Much has been written about the tendency of current climate models to overestimate recent warming and thus their unfitness to accurately project future warming. The graphs below, prepared by Dr. John Christy, illustrate this tendency for the CMIP5 and CMIP6 model ensembles.

Two points are obvious from these graphs. First, the large number of models produce very significantly varying future projections among themselves. Second, all but one of the models produce individual projections widely at variance from observations over the period. As Dr. Christy notes on the first graph above, “the models and observations are not from the same physical system”. Since the observations, though “adjusted”, are from the physical system we call earth, we can consider them to be near-real. This leads to the obvious conclusion that the model projections are not “real” for the physical system we call earth.

The “adjustments” to the near-surface temperature have characteristically reduced the measured temperatures, as shown in this blink comparator prepared by Tony Heller. This blink comparator deals only with the US, but clearly illustrates the reductions to historical raw data. This illustration shows increases to recent data, though that is now far less common as the result of the US Climate Reference Network. The US CRN produces data there is no reason to “adjust”, which makes “adjusting” other US temperature more problematic.

The history of negative “adjustments” to historical near-surface temperature data might represent a possible explanation for the tendency of climate models to over-project future temperatures. The climate models are typically “tuned” to historical temperatures through hindcasting. This also assures that there are no glaring errors in the function of the models. However, this “tuning” is done to “adjusted” temperature histories in which older temperatures have been reduced, resulting in a steeper temperature increase trend over the period of the temperature record. Therefore, the “tuned” models are tested against a temperature record which shows an artificially rapid increase in historical temperatures. The “tuned” models would then be expected to project an artificially rapid future increase in temperatures as an extension of the “adjusted” historical trend.

The CMIP5 models have progressively falsified themselves; that is: “The hypothesis failed.” The CMIP6 models also appear to be in the process of falsifying themselves. Both model ensembles projected future temperature increases over the 1979-2020 period approximately three times the observed temperature increases. They clearly do not form an acceptable basis upon which to dramatically revise the energy and economic structures of the nations of the globe at the cost of trillions of dollars.

The model projections are the sole basis for the concerns regarding a “climate crisis”, “climate emergency” or “existential threat” resulting from continued emissions of “greenhouse gases” resulting from human activity. The consensed climate science community has acknowledged that the models are “running hot”, that the situation is unacceptable and unsustainable, and that it must be addressed. The consensed climate science community has also acknowledged the need to establish a more accurate global near-surface temperature measurement network, similar to the US CRN.

It is long past time to end the climate science practice of Frantic Researchers Adjusting Unsuitable Data.

From: Climate Etc.

By: Judith Curry

Date: October 6, 2021

IPCC AR6: Breaking the hegemony of global climate models

"A rather astonishing conclusion drawn from reading the fine print of the IPCC AR6 WG1 Report.

Well, I’ve been reading the fine print of the IPCC AR6 WG1 Report. The authors are to be congratulated for preparing a document that is vastly more intellectually sophisticated than its recent predecessors. Topics like ‘deep uncertainty,’ model ‘fitness-for-purpose’ (common topics at Climate Etc.) actually get significant mention in the AR6. Further, natural internal variability receives a lot of attention, volcanoes a fair amount of attention (solar not so much).

If we harken back to the IPCC AR4 (2007), global climate models ruled, as exemplified by this quote:

“There is considerable confidence that climate models provide credible quantitative estimates of future climate change, particularly at continental scales and above.”

The IPCC AR4 determined its likely range of climate sensitivity values almost exclusively from climate model simulations. And its 21st century projections were determined directly from ..."

IPCC AR6: Breaking the hegemony of global climate models

“Government is like a baby. An alimentary canal with an appetite at one end and no sense of responsibility at the other.”, Ronald Reagan

The utility industry challenges discussed in the previous commentary, Reliability Roulette, have already begun to manifest themselves in service interruptions, first in California and most recently in Texas. In both cases, the blame game began immediately, based largely on impressions, limited information and CYA. The stage is already being set for more of the same.

The renewable energy industries assert that there are large backlogs of renewable energy projects currently being delayed by regulatory approvals, financial uncertainty and issues with transmission access. While these issues are not new, they have become more visible and more contentious with the establishment of the Administration wish to transition the electric industry to net zero emissions by 2035. While government is demanding this massive change in the electric utility industry’s supply portfolio, it accepts no responsibility for the impediments it places in the industry’s path.

The renewable energy industries are taking much the same position as the government regarding the required transition. Generators seeking to sell power to the electric grid have historically constructed their facilities in relatively close proximity to utility transmission facilities and provided the facilities necessary to make the grid connection. However, renewable generators frequently do not have the flexibility to locate facilities with convenient access to the grid. They currently take the position that it is the responsibility of the grid operators to extend the grid to their facilities. This has the added benefit of transferring the investment required to connect to the grid from the renewable generator to the grid operator, reducing the overall investment in the renewable generating facility and lowering the cost of the power generated.

The addition of intermittent, non-dispatchable generation to the transmission grid in growing quantities and the consequent displacement of dispatchable generating capacity produces the need to store excess renewable power, when available, to meet customer demand when intermittent power is not available in sufficient quantity. The renewable energy industries are taking the position that the construction and operation of grid-scale energy storage facilities, required only by the intermittency of their generation, is nonetheless the responsibility of the grid operators. This further reduces the apparent cost of the renewable generation, while transferring intermittency related costs to the grid operators.

As increased renewable generation replaces dispatchable generation, it produces a dead weight loss of the investment in the dispatchable facilities while creating a demand for increased grid-scale storage. Remaining dispatchable generators are operated less frequently, increasing the cost of the power they provide.

This situation positions the renewable energy industries, which rely on federal and state subsidies, incentives and generation preferences, to tout their low cost while blaming government for regulatory delays and the grid operators for problems with grid access, grid adequacy and grid-scale storage adequacy as well as the rising cost of electricity despite the lower cost of their renewable electricity.

Of course, any similarity to the baby described by former President Reagan above is purely coincidental.

From: Watts Up With That

By: Andy May

Date: September 21, 2021

The Greenhouse Effect, A Summary of Wijngaarden and Happer

"The phrase “greenhouse effect,” often abbreviated as “GHE,” is very ambiguous. It applies to Earth’s surface temperature, and has never been observed or measured, only modeled. To make matters worse, it has numerous possible components, and the relative contributions of the possible components are unknown. Basic physics suggests that Earth’s surface is warmer than it would be with a transparent atmosphere, that is no greenhouse gases (GHGs), clouds, or oceans. If we assume Earth is a blackbody, then subtract the solar energy reflected, from the hypothetically non-existent clouds, atmosphere, land, ice, and oceans; we can calculate a surface temperature of 254K or -19°C. The actual average temperature today is about 288.7K or roughly 15.5°C. This modeled difference of 35°C is often called the overall greenhouse effect.

A blackbody is usually defined as a perfectly black cavity kept at a constant temperature. All energy that enters the cavity is absorbed by the cavity walls, and they emit exactly the same amount of energy, but the wavelength of the emitted radiation is not the same as the energy captured. Instead, the emitted radiation has a wavelength determined by the cavity temperature, which is held constant. The Earth is nothing like this. It isn’t black and both the atmosphere and the oceans absorb and redistribute solar energy, often the absorbed energy is circulated for a long time, even centuries or millennia, before it is reemitted. A blackbody absorbs and reemits energy with a delay of less than a second. Earth’s surface temperature is not constant, like a blackbody’s temperature, it varies a lot by latitude, altitude, season, and/or ocean depth. The Moon has a calculated blackbody temperature of 270K, no atmosphere or oceans, and an average temperature, at the equator and low latitudes, of around 215K, so even the" ...

The Greenhouse Effect, A Summary of Wijngaarden and Happer

Service reliability has been a hallmark of the utility industry, which has made massive investments to assure reliable service. High reliability is important to the utilities’ customers and is demanded by utilities’ regulators. However, there is continuous tension among utilities, regulators and customers regarding the nature and scope of facilities investments required to assure adequate supply and  acceptable reliability while controlling costs and rates.

The electric utility industry has approached reliability by installing numbers of high reliability, high availability, dispatchable fossil fuel and nuclear generating stations, while taking advantage of available hydroelectric generation. Reliability was further enhanced by the establishment of regional transmission organizations which could move power among the member utilities. Market growth was accommodated by adding generators and transmission capacity. Response to changing demand was accomplished by adjusting the number and type of generators in service, the outputs of the individual generators and by allowing system voltage to vary within narrow limits. Storage was limited to hydroelectric generation, including pumped storage facilities.

The natural gas industry approached reliability by acquiring gas from numerous geographically and geologically spaced wells and moving the gas to market through numerous pipelines. Response to changing demand was accomplished through wellhead flow management, pipeline compressor control and near-market and in-market storage in abandoned gas wells and above ground gas holders.

Both industries have also implemented various approaches to demand management, including contractual service interruption or reduction in exchange for reduced rates. These approaches have worked well over numerous decades. However, both industries are now being challenged by federal and state actions in response to the perceived threat of climate change.

The electric industry is being required to acquire increasing quantities of energy from intermittent sources of renewable energy, primarily wind and solar energy. These intermittent renewable energy sources are not reliably available and are not dispatchable under utility or RTO control. Regulations also frequently require the utilities to accept all electricity generated by these renewable facilities when it is available while adjusting the operation of dispatchable generators to meet the balance of demand. The challenge of managing the grid increases as the percentage of intermittent renewable generation increases, since the intermittent generator output can fluctuate rapidly and increasing dispatchable generation must be available to meet demand.

The natural gas industry is facing federal and state restrictions on exploration for and production of additional sources of supply. The hydraulic fracturing technology which has greatly expanded natural gas availability and reduced prices is being challenged by environmentalists. The continuing and expanded use of natural gas is also being challenged since its combustion produces CO2, which is viewed as a contributing cause of climate change.

Both utility industries are also being challenged by environmentalist opposition to the construction of new transmission capacity to move energy to growing markets.

These issues are adversely affecting the ability of both electric and gas utilities to assure reliable service at reasonable cost and are thus in conflict with the demands of both regulators and customers.

From: The Honest Broker Newsletter

By: Roger Pielke Jr.

Date: September 20, 2021

A Coal Exit Treaty Can Radically Simplify and Accelerate Climate Policy

"A focus on eliminating coal power offers a much more pragmatic approach to deep decarbonization

While there are encouraging signs that the global emissions of carbon dioxide have plateaued, achieving deep decarbonization of the global economy remains a massive challenge. In this post I’ll propose a complementary approach to climate policy that is far more pragmatic than the current architecture of global climate policy.

For decades, climate policy has focused on managing outcomes, which at various times have included the atmospheric concentration of greenhouse gases and more recently, global average surface temperatures. Such outcomes are useful for setting goals – like the well-known 2 degree Celsius temperature target -- but are poor choices for management, because such outcomes can only be indirectly managed. Policy typically works better when focused on managing causes rather than consequences.

Climate policy, broadly conceived, includes an incredible array of issues touching upon just about every facet of policy making, but here I focus on a narrow but important element of climate policy, the emission of carbon dioxide from the burning of fossil fuels. Here the math is incredibly simple: if the temperature targets of the Paris agreement are to be reached, then carbon dioxide emissions from the burning of fossil fuels necessarily ..."

A Coal Exit Treaty Can Radically Simplify and Accelerate Climate Policy