Author Archive for CERP Team

High Equity, Low Equity, and the “Equity Band”

The Climate Equity Reference Calculator estimates national fair shares of the global mitigation effort based on each country’s capacity and responsibility, according to user choices across a number of key “Equity Settings.” In both the recent National Fair Shares report and the Comparable Effort Worksheet, results are presented in terms of an “Equity Band” that spans a broad set of possible equity settings and thus gives an instructively comprehensive range of results for each country.

This Equity Band is bounded by a “Low Equity” setting on one side and a “High Equity” setting on the other. While such limits cannot be uniquely and objectively established, they are defined here in a way that captures meaningfully distinct perspectives on two hotly debated issues in climate equity. The first is the level of progressivity that is appropriate to a definition of national capacity, and the second is appropriate time frame for considering a nation’s historic responsibility. In this memo, we briefly describe how the High Equity setting and Low Equity setting (and an intermediate Medium Equity setting) are defined along these two dimensions.

Capacity and progressivity

The Calculator defines national capacity in terms of income. Income is typically considered in a progressive manner in national tax policy; analogously, it can be considered in a progressive manner for the purposes of defining capacity. In general, we consider three alternative settings:

  • In the “No Progressivity” case, all income within a nation counts toward its capacity. There is no income threshold below which individual income is exempted from national capacity. Rather, when calculating capacity, each dollar of income – even for the poorest of the world’s people – counts as much as each dollar of the world’s richest. Importantly, this setting is inconsistent with the conventional progressive approach that virtually all societies have adopted for the purpose of income taxation, and it is difficult (if not impossible) to justify in equity terms. Nonetheless we include it here as a lower bound.
  • In the “Weak Progressivity” case, there is a low income threshold below which individual income is exempted from the calculation of national capacity.[1] This weak case is used to define “Medium Progressivity” cases, in which the “development threshold” is set at $7,500 (approximately $20/day). This level is just a bit above a global poverty line that reflects empirical observations, so it too should be taken as a low estimate of “medium” progressivity.
  • In the “High Progressivity” case, a lower income threshold is set at $7,500 (as in the “Weak Progressivity” case), with income above this threshold counting toward national capacity at a steadily rising rate, until it reaches an upper income threshold of $50,000, above which all income is counted towards national capacity. These settings increase the overall progressivity of the income calculation just as a graduated tax schedule raises the progressivity of an income tax.[2]

Historical responsibility and time frame

The Calculator defines national responsibility in terms of cumulative emissions. A key setting then is the initial year from which historic emissions are included in the reckoning of a country’s responsibility. We consider three alternative settings here.

  • The low case is defined as “Responsibility since 1990.” This date corresponds roughly to the time when negotiations for an international legal agreement to limit GHGs began in earnest and the risks of rising GHGs were acknowledged by the IPCC.
  • The medium case is defined as “Responsibility since 1950.” This date marks a useful middle setting. It defines a period in which responsibility is comprehensible in terms of human lifetimes, reflects roughly the useful lifetimes of much infrastructure, and avoids some of the historical discontinuities that occur when, for example, wars remake national boundaries.
  • The high case is defined as “Responsibility since 1850.” This date defines responsibility as cumulative emissions since a date that roughly corresponds to the time at which carbon dioxide emissions from fossil fuel combustion reached significant levels. This is also the earliest date for which plausible emissions data exist.

Combining Capacity and Responsibility into High, Medium, and Low Equity Settings

There are nine possible combinations of the three capacity settings and three responsibility settings. However, we here group these into only three cases, which more simply capture the broad “equity band” spanned by the possible settings.

  • “Low Equity” settings: No Progressivity and Historical Responsibility since 1990
  • “Medium Equity” settings: Weak Progressivity and Historical Responsibility since 1950
  • “High Equity” settings: Strong Progressivity and Historical Responsibility since 1850

While we refer to these combinations as Low Equity, Medium Equity, and High Equity, we do not imply that the High Equity case is objectively “more equitable” than Low Equity, for this is ultimately a normative judgment. Rather, these references simply refer to the fact that the High Equity case is the most progressive and includes the most historical responsibility, while the Low Equity case is the least progressive and includes the least historical responsibility.

Using such a broad Equity Band leads inevitably to fair share results that can span a significant range, as is evident in the National Fair Shares report and the Comparable Effort Worksheet. By accommodating a broad range of equity perspectives, such an approach allows us to escape the debate between, on the one hand, the claim that equity is an entirely subjective matter, a mere battle of opinions, and, on the other hand, the claim that one or another equity approach is the precisely “right one.” Equity Bands offer a quantitative framework within which explicit choices between well-specified approaches – e.g. more or less progressive responsibility and capacity indexes – can be assessed and compared in a common framework without being over-specified and reified. While this approach inevitably yields ranges instead of distinct numbers, it also yields higher confidence, as a consequence of having understandable results that transparently and traceably expresses a set of explicit ethical-political choices.

[1] Correspondingly, emissions corresponding to income below the same threshold do not count toward Responsibility.

[2] The Calculator allows the user to set the lower and upper thresholds at any income level. It refers to the lower income level as the “development threshold” and the higher income level as the “luxury threshold”. These terms are used because they are suggestive of a typical and ethically compelling interpretation, where the lower threshold is chosen to reflect an income level modestly above a global poverty line, and the upper threshold is chosen to reflect an income level above which all income is discretionary, and much of it is spent for consumption well beyond basic comforts.

Zero Carbon, Zero Poverty – The Climate Justice Way

Zero Carbon, Zero Poverty – The Climate Justice Way, a major new report written for the Mary Robinson Foundation: Climate Justice by Sivan Kartha and Paul Baer of the Climate Equity Reference Project, breaks new ground in global climate justice theory and analysis.  Here, from the executive summary, are its main conclusions:

• There is strong evidence that a rapid and total or nearly-total carbon phase-out will be technically feasible, both for developed and developing countries.

• Economic analyses suggest that a rapid carbon phase-out can be achieved at an aggregate global cost that is affordable, and much less than the potential costs of climate impacts.

• Nonetheless, a rapid carbon phase-out will be very demanding for all countries, especially developing countries, and presents potential risks to human rights.

• Even greater risks to human rights than the risks posed by aggressive mitigation action arise from the profound impacts of climate change, especially if temperature increase exceeds 2°C, which becomes increasingly likely if mitigation is delayed.

• There is good reason to believe that risks posed by mitigation can be dealt with, provided there is an ambitious and fairly shared global effort to achieve a rapid carbon phase-out while preserving human rights, and a commitment to integrating human rights and equity in all national climate policies.

Is all of this already clear? Perhaps it is, or perhaps not. In any case, these points are rarely made as clearly, or defended as well, as they are here.

National Fair Shares: The Mitigation Gap – Domestic Action and International Support

Our new report, National Fair Shares, summarizes the analysis embodied in the Climate Equity Reference Calculator, a generalized approach to considering equitable effort-sharing in an international climate agreement. This approach is designed to preserve “equitable access to sustainable development” even as it drives an extremely ambitious global mitigation program, and is particularly timely as countries prepare to submit their Intended Nationally Determined Contributions (INDCs) to the UNFCCC.

In particular, this analysis finds that a nation’s fair share of the global mitigation effort can be quite different from its domestic mitigation potential. Countries with relatively high capacity and responsibility are generally found to have fair shares that greatly exceed their own domestic mitigation potential; therefore, if they are to fulfill their entire fair share, they are required to contribute financial and technological support to other countries. Conversely, countries with relatively low capacity and responsibility are able to act entirely within their own borders. It is assumed that they use international support to undertake mitigation in excess of their own fair shares of the global mitigation effort, and by so doing exploit their full national mitigation potentials. As such, this analysis is informative not only for assessing countries’ INDCs with respect to domestic mitigation action, but international support as well.

From the abstract:

In this report, we systematically apply a generalized and transparent equity reference framework, with the goal of quantitatively examining the problem of national fair shares in a global effort to rapidly reduce greenhouse gas emissions. This framework is based upon an effort-sharing approach, uses flexibly-defined national “responsibility and capacity indicators,” and is explicitly designed to reflect the UNFCCC’s core equity principles. It can be applied using a range of possible assumptions, and whatever values are chosen, they are applied to all countries, in a dynamic fashion that reflects the changing global economy. In this report, we present results for twelve representative countries and a selected set of illustrative “cases.”

The quantitative analysis in this report is based upon the Climate Equity Reference Calculator, an online tool and database that allows the user to select “equity settings” relating to key equity-related parameters, including responsibility, capacity, and development need. These settings are then used, together with standard demographic and macroeconomic indicators (e.g., national population, GDP and carbon-intensity) to calculate implied national fair shares of the global mitigation effort. Importantly, this fair share is expressed as a sum of domestically- and internationally-supported mitigation.

We provide illustrative results for various alternative levels of ambition, for various equity settings, and for various estimates of national emissions reductions. We also show that the differences between the cases are much less significant than the similarities, and that a great deal of the detail can therefore be set aside in favor of an “equity band” that is bound by “High Equity Settings” on one side and “Low Equity Settings” on the other. We have defined this equity band to span a wide range of perspectives on fairness, though it is easier to argue that the “Low Equity Settings” are “too low” than it is that the “High Equity Settings” are “too high.”

For a short summary of the report (6 pages) see here.

Global Climate Change Policy: Will Paris Succeed, Where Copenhagen Failed?

A nice precis of the current situation in the negotiations — as we turn the corner and head for Lima, and then for Paris — was just published by Ian McGregor in e-international relations, here.  The piece is notable for its clarity about the international support being as much a part of a nation’s fair share as its domestic emissions, and, notably, about the notion of “emerging shares.”  To wit:

“As CAN pointed out recently, when a country submits it INDC it is implicitly choosing a temperature target, the one that would be realized if all other countries were to act in a comparable manner, relative to their fair share of the global effort required.  If a country proposes a contribution that amounts to less than its fair share of the global effort required to keep temperature rise well below 2°C, then that country is, in effect, proposing an overall global temperature increase that exceeds 2°C.”

Many of the details will be familiar to the readers of this site, but the piece is nonetheless notable for its detailed realism, and its familiarity with the equity debate within the negotiations, and for the detail in which it lays out civil-society position on the fair shares problem.

Check out


This elegant system, put together by Friends of the Earth EWNI and Jubilee South Asia Pacific Movement on Debt and Development, is based on the “responsibility and capacity index” analysis embodied in the Climate Equity Reference Calculator. Its map interface is very cool, and simple to use, for it presents only a single Equity Settings profile. This is, for the record, a “high equity” profile defined by the Strong 2C pathway, high progressivity settings (including a $50,000 luxury threshold), a 1850 historical responsibility start date, a 50/50 responsibility/capacity weighting and “capacity adjusted” domestic emissions.

Norway’s fair share of an ambitious climate effort

The first of our “next generation” of country reports was just done, for Norway, together with Norwegian Church Aid and the ACT Alliance.

The report — Norway’s fair share of an ambitious climate effort — is the firs major report that we have done since we updated and generalized the Greenhouse Development Rights system, and re-released our calculator as the Climate Equity Reference Calculator.

This report is also notable for restricting itself to the “Strong 2C mitigation pathway.”  In other words, the very challenging numbers in this report are associated with an extremely ambitious global mitigation transition, one that would actually have a good chance of stabilizing the climate system.

What would a fair UN climate change deal look like?

Great piece — here – on the Responding to Climate Change site on our Climate Equity Reference Calculator.

Great but not perfect, alas.  For example, the opening tag says “New equity calculator says UK needs to cut emissions 94% by 2020, US by 73% and China just 9.4%.” And of course this will be read as implying that the is the one sole result of the calculator.

Here’s comment that we made soon after the piece was posted:

“Not that I’m complaining about the publicity, but one clarification.   Where the RTCC author says . . .

China’s emission trajectory for 2020 is a whopping 16,688 MtCO2e, just under the target total for the whole world. But the ERF calculator says it just needs to shave off 1,575 MtCO2e, or 9.4%.

What he should have said is something like . . .

China’s emission trajectory for 2020 is a whopping 16,688 MtCO2e, not much less than the mitigation target for the whole world. Of this, according to the ERF calculator, it needs to itself finance mitigation of 1,575 MtCO2e, or 9.4%.  (It’s “fair share”).  The total mitigation that needs to take place within its borders is, of course, much greater, and amounts to about 4,673 MtCO2e, or 28% of China’s projected 2020 baseline emissions.

The problem is that this last number is hard to read out from the Calculator UI as it currently stands.   We will fix this.”


The road to Paris, the Climate Equity Reference Calculator, and you

Recently, we were invited to do a post on our “equity reference framework” work for the MAHB — that’s Millennium Alliance for Humanity and the Biosphere, in case you were wondering.  Pronounced “MOB.”  It’s an interesting project, and it has a significant foothold in the fluid, fertile space where environmental scientists and civil society “actors” meet.

The post turned out to be a good introduction to the Climate Equity Reference Calculator, one that situates it firmly in the global climate justice debate, as it’s unfolding in the international climate negotiations.   Here a link to it.  And here’s the lead . . .

“It’s about 18 months now until the Paris climate showdown.

The good news is that there’s quite a lot happening.  The clarifying science, for example, is no longer easily denigrated.  The IPCC’s 2°C carbon budgets, the new age of “extreme weather,” the fate of the Arctic, these can no longer be cast as fervid speculations.  Denialism – at least classic denialism – has peaked.  This is a time of consequences, and we all know it.

But what about Paris?  Why do I even mention the international climate negotiations?  Don’t we all know that the North/South divide is unbridgeable?  Don’t we all know that the wealthy world will never provide the finance and technology support that’s needed to drive deep and rapid decarbonization in the emerging economies?  Don’t we all know that the prospect for a meaningful breakthrough in the climate talks is nil?

In fact, we do not.”

Talking dollars and cents: Big questions about the Green Climate Fund

Which countries will contribute to the Green Climate Fund, and how much?

What will it take to get to the $15 billion target?  The Greenhouse Development Rights framework is still one of the best places to go for an answer.  Witness this comment by Annaka Peterson Carvalho is the Senior Program Officer of the Adaptation Finance Accountability Initiative, led by World Resources InstituteOverseas Development Institute, and Oxfam.

Yeb Saño publicly endorses GDRs

In a wide ranging and insightful interview, Yeb Saño — the Philippines lead who rose to fame when, saddened by the devastation of Typhoon Haiyan and frustrated by the slow pace of international action, he fasted through two weeks of U.N. climate change treaty talks, has just publicly endorsed Greenhouse Development Rights.

The interview, on ClimateWire, is wide ranging and very interesting.  Here’s the relevant passage:

CW: According to the latest IPCC report, about half of cumulative emissions between 1750 and 2010 occurred in the last 40 years. Much of that was from China. Doesn’t that beg the question — how much longer will emerging economies be able to use the historic responsibility argument to avoid taking legal obligations, as well?

Saño: Yes, as time goes by, everyone’s historic responsibility will increase. Yes, some emerging economies have been growing faster than we’ve expected. The problem with the optic there is, these countries have done even more than Annex I countries. We’ve seen the China story change drastically in the last decade, and then shift again. Recently, they’ve made some really significant pronouncements where the use of coal is concerned. So it becomes a lot more difficult to keep on pointing the finger at emerging economies when they are also emerging as doing a lot more.

We feel that every ton of carbon dioxide that is emitted into the atmosphere has a corresponding responsibility from where it is emitted from. How do we distribute that? That is the challenge. The Philippines’ point of view is that every country can participate in this regime. I think the key is not to distribute responsibility according to merely the level of emissions per country, but there has to be a certain consideration of the level of welfare of the citizens of each country.

It’s a critical balancing act. Countries like Saudi Arabia and even China will always have the right to invoke the climate convention. [But] speaking from the point of survival, I think we have reached a point where Annex I countries alone can’t solve climate change. That is a fact. We have gone way past that point where rich countries can solve climate change alone. The solution will have to lie in global solidarity, and each country that can contribute must contribute.

CW: And yet Saudi Arabia, with which the Philippines aligns itself in the U.N. talks, has maintained that the contribution of non-Annex I countries in any new agreement should be only to adapt to climate change, while Annex I countries should continue to be the ones to take legal responsibility for cutting emissions. So which is it?

Saño: We cannot force countries which are not Annex I countries to take on obligations of the same nature as Annex I countries. However, I think countries must set aside narrow national interests and be able to contribute in an ambitious way, not just towards a post-2020 regime but an immediate regime. My country cannot afford to wait six more years for the whole world to take action, and six years of no legally binding emissions cuts for me is a catastrophe.

This is a global endeavor, and if we are to subscribe to narrow national interests, we can go our separate ways and forget about solving climate change.

What the Philippines, I think, would like to advocate for is a Greenhouse Development Rights approach. I know that’s not going to resonate well with many countries, both in the north and in the south, but it’s really about rights. It’s about the life of a single Filipino having the same value as one American or one European. We all deserve equitable access to the planet. That should be the primary parameter, rather than economic competitiveness.