Question:
You are given the full text of a scientific research paper.

    Summarize the **research methods** used in the study in a way that is informative for policy audiences. Your response should:
    - Describe the overall study design, data sources, tools, and models used
    - Avoid unnecessary technical details or equations
    - Use accessible but precise language

    Write a short paragraph suitable for the “Scientific Research Study Methods” section of a policy brief.

    Scientific Research Paper:
    Nature Climate Change
nature climate change
https://doi.org/10.1038/s41558-025-02283-4
Analysis
Fossil fuel subsidy reforms have become
more fragile

Paasha Mahdavi
  1
, Michael L. Ross
  2
 & Evelyn Simoni2
Since the mid-2010s, many governments have pledged to reduce their
subsidies for fossil fuels. Yet, it is unclear whether these reforms have been
implemented, with prior studies showing conflicting results. Here we collect
original monthly data on the 21 countries with the largest gasoline subsidies
in the 2003–2015 period and evaluate their reform efforts from 2016 to
2023. Since 2016, there has been an increase in the frequency and ambition
of subsidy reforms but a drop in their durability: just 30% of the reforms
survived for 12 months, and only 9% survived for 36 months. Subsidies rose
for 12 countries in our sample and were virtually unchanged in the other
9. This pattern calls into question the effectiveness of recent strategies for
reducing fossil fuel subsidies.
One of the most cost-effective ways to reduce carbon emissions is by
eliminating fossil fuel subsidies1,2. These subsidies boost the consump-
tion of fossil fuels and, hence, slow the transition to renewable energy3;
increase road traffic, air pollution and road fatalities, all of which dam-
age public health4,5; and can have a crippling impact on government
revenues6.
Yet, they are also difficult to abolish. Many intergovernmental
organizations—including the World Bank, the International Monetary
Fund (IMF) and the International Energy Agency—have urged gov-
ernments to eliminate these subsidies. At the 2021 United Nations
Climate Change Conference (COP26) in Glasgow, Scotland, govern-
ments pledged to phase down ‘inefficient fossil fuel subsidies’. But
political leaders are often wary of reform, realizing that higher fuel
prices are unpopular and could lead to protests that could threaten
their government7,8.
In the early 2010s, international organizations stepped up their
advocacy work for fossil fuel subsidy reform, sponsoring new initia-
tives, reports and conferences9. The IMF began to emphasize subsidy
reform in its policy recommendations10. Subsidy reforms were directly
incorporated into the Sustainable Development Goals (SDG 12.c) in
September 2015, and 15 countries included fossil fuel subsidy reforms
in their Intended Nationally Determined Contributions for the Decem-
ber 2015 Paris conference11. It is unclear whether these initiatives led
to a reduction in subsidies. One study found that, from 2015 to 2020,
41 countries reformed consumer fossil fuel subsidies12; yet, according
to the International Energy Agency, from 2015 to 2022 these subsidies
rose from US$183 billion to US$343 billion (ref. 13).
The reform of fossil fuel subsidies is difficult to study in part
because they are hard to measure. In many countries, subsidies rise
and fall over time owing to a mixture of market forces and government
policies that can be hard to disentangle. Governments often provide
unreliable information about their own policies: they may announce
reforms but fail to implement them or, conversely, adopt reforms
quietly in an effort to avoid protests.
To better measure government policy reforms, we adopt a novel
approach. Like other scholars, we focus on consumer subsidies for
gasoline, which can be calculated using the widely accepted price gap
method14. We begin by calculating the average implicit gasoline tax or
subsidy for all countries from 2003 to 2015, using the Ross–Hazlett–
Mahdavi dataset15. We then take as our sample those countries that,
on average, were net subsidizers during this 13-year period. These 21
countries account for 97% of all gasoline subsidies in the 2003–2015
period. They constitute a ‘most likely’ sample: if progress has been
made since 2016 in subsidy reform, we are most likely to find sub-
stantial reforms in these 21 countries. Although they are all fossil fuel
exporters, they vary widely in economic and social development.
They also represent many locations across the Global South, including
Sub-Saharan Africa, Latin America, the Middle East, Southeast Asia
and the Caspian Basin (Table 1).
We then leverage a valuable feature common to these 21 countries.
All of them used government mandates to set fuel prices and kept them
fixed for months or years at a time. Hence, whenever the government
raised the nominal per-litre price by at least 10%—effectively reducing
the subsidy for their citizens—we code it as a reform. We also measure a
Received: 24 September 2024
Accepted: 18 February 2025
Published online: xx xx xxxx
 Check for updates
1Department of Political Science, Bren School of Environmental Science and Management (by courtesy), University of California, Santa Barbara, CA, USA.
2Department of Political Science, University of California, Los Angeles, CA, USA.
 e-mail: paasha@ucsb.edu; mlross@polisci.ucla.edu

Nature Climate Change
Analysis
https://doi.org/10.1038/s41558-025-02283-4
Our study makes three contributions to research on climate policy
and politics.
First, it documents the remarkable frequency with which fossil fuel
subsidy reforms have failed. The 21 countries in our sample enacted
132 reforms during the 2000–2023 period. All but nine of them (6.8%)
eventually failed. We disaggregated these failures by type and period
to better understand the obstacles to reform.
Second, our study helps to resolve conflicting interpretations of
the recent trend in fossil fuel subsidies. Some studies describe pro-
gress in rolling back fossil fuel subsidies18, while others show that the
total value of these subsidies has increased over the same period5,13.
Our analysis resolves this paradox by demonstrating that the rising
frequency of reforms after 2015 was offset by a commensurate decline
in reform duration.
Finally, our study sheds light on the disappointing record of sub-
sidy reforms, especially since 2016. By December 2023, no country
in our sample had considerably lower subsidies than in January 2016.
We are cautious about extrapolating our finding that there has been
little net progress to other types of climate policy: fuel subsidies are
exceptionally hard for governments to change, especially in oil- and
gas-producing countries. We believe that our findings should cause
policy advocates to look for new strategies that could make fossil fuel
subsidy reform more durable and, hence, more effective.
Results
We track two varieties of subsidy reform. The most common type is
price reform, which we define as an increase in the nominal price of
gasoline by 10% or more in local currency units in a single month. For
robustness, we also track an alternative measure that indicates a nomi-
nal increase of 25% or more over 3 months (Extended Data Fig. 5). Price
reform ends (or ‘fails’) if the subsidy returns to its pre-reform level,
which can happen through two mechanisms: the government may
explicitly reverse the price increase, a process we call backtracking;
or the government may maintain the post-reform price, but its value
disappears through inflation, a falling exchange rate or rising global
oil prices. We refer to the latter process as erosion.
The second type is fixity reform, which occurs when a government
stops using fixed prices and subsidies altogether, allowing gasoline
prices to fluctuate in response to changing oil prices for at least three
consecutive months. A fixity reform can fail in two ways: if the govern-
ment reimposes fixed prices for three or more consecutive months; or if
the government interferes with the market price to restore a substantial
subsidy (which we define as a subsidy exceeding 20 cents per litre in
constant 2015 US dollars) for three consecutive months.
Incidence of reform
From 2000 to 2015, the countries in our sample adopted an average of
0.24 reforms per year per country; from 2016 to 2023, the reform rate
rose to 0.38 per year, an increase of more than 50% (Table 2). There were
more reforms in 2015 and in 2016 than in any other year.
second type of reform, when a government transitions from fixed prices
to floating, unsubsidized, market-based prices. We refer to increases in
the fixed price as price reforms and shifts from fixed to floating prices
as fixity reforms. Because earlier studies suggest that many reforms are
transitory16, we measure both the initiation of reforms and their dura-
tion. To measure changes, we compare the frequency and duration of
reforms from the January 2000 to December 2015 period, leading up
to the 2015 Paris conference, with the January 2016 to December 2023
period following the end of the conference. While the final text of the
Paris Agreement did not mention subsidy reform, the December 2015
conference was a landmark in the global effort to promote climate
policies17 and provides a useful cut point for our analysis. Our core
results are similar if we use December 2014 instead (Extended Data
Fig. 6). They are also unchanged if we drop any country in our sample
(Extended Data Figs. 7 and 8).
We have three broad findings.
First, since 2016 there has been a notable increase in the frequency
of reforms. From 2000 to 2015, the countries in our sample collectively
initiated an average of 0.24 price reforms per country year; from 2016
to 2023, they initiated about 0.38 reforms per country year, a 58%
increase. There was also a sharp rise in fixity reforms, which we regard
as more ambitious than price reforms.
Second, reforms were already fragile in the pre-2016 period, and
grew even more fragile after 2015. From 2000 to 2015, only 45% of all
subsidy reforms survived at least 12 months and only 22% survived for
36 months; from 2016 to 2023, 30% survived for 12 months and only 9%
lasted 36 months. Ambitious reforms were especially fragile.
Finally, subsidies per litre of gasoline rose substantially in 12 coun-
tries in our sample and changed little in the other 9. On average, the
value of the per-litre subsidy in our sample rose 65.1% over these 8 years,
equivalent to an annual increase of 6.5%.
Table 1 | Changes in net taxes from 2016 to 2023
Taxes Q1–2016
Taxes Q4–2023
Difference
Angola
0.52
−0.30
0.82
Iran
−0.07
−0.55
0.48
Indonesia
0.13
−0.24
0.37
Sudan
0.42
0.07
0.36
Iraq
−0.02
−0.31
0.30
Libya
−0.29
−0.56
0.27
Malaysia
0.01
−0.24
0.26
Egypt
−0.07
−0.30
0.23
Algeria
−0.13
−0.33
0.20
Bahrain
−0.11
−0.29
0.19
Azerbaijan
0.04
−0.13
0.17
Kuwait
−0.20
−0.37
0.17
Qatar
−0.04
−0.13
0.09
Oman
−0.06
−0.12
0.06
Nigeria
0.06
0.01
0.05
Ecuador
−0.05
−0.09
0.04
Trinidad and Tobago
0.08
0.10
−0.02
United Arab Emirates
0.03
0.06
−0.03
Myanmar
0.05
0.10
−0.05
Saudi Arabia
−0.16
−0.10
−0.06
Average level of tax for the first quarter of 2016 and the final quarter of 2023, in real US
dollars per litre. Negative values reflect subsidies; positive values reflect taxes. The difference
shows the increase in the subsidy over this period (conversely, the decline in the tax). Note:
Venezuela is excluded due to the unavailability of reliable exchange rate data in IMF records
from 2018 onwards.
Table 2 | Summary statistics of reform onset and durability
2000–2015
2016–2023
Rate of price reform onset (per country per year)
0.22
0.25
Rate of fixity reform onset (per country per year)
0.02
0.13
Reforms lasting at least 12 months (% of total
reforms in the period)
44.74
30.36
Reforms lasting at least 36 months (% of total
reforms in the period)
22.37
8.93
Failure rate from backsliding (% of total reforms
in the period)
0.09
0.34
Failure rate from erosion (% of total reforms in
the period)
0.87
0.55

Nature Climate Change
Analysis
https://doi.org/10.1038/s41558-025-02283-4
Duration of reform
Subsidy reforms tend to be short-lived, and reforms failed more
quickly after 2016. From 2000 to 2015, 45% of all reforms survived
for 12 months, and 22% survived for at least 36 months; from 2016 to
2023, only 30% survived for 12 months, and 9% survived for at least
36 months (Fig. 1).
Depth of reform
Over the full 2000–2023 period, 80% of all reforms were price reforms
and 20% were fixity reforms. This ratio changed over time. From 2000 to
2015, we found an average of just 0.024 new fixity reforms per country
year. From 2016 to 2023, however, they occurred at a rate of 0.13 new
reforms per country year, a fivefold increase. Fixity reforms accounted
for most of the overall rise in the frequency of reforms after Paris.
The advantages of fixity reforms are self-evident: floating prices are
not automatically eroded by inflation, currency depreciation or global
oil shocks. In theory, fixity reforms should be more durable than price
reforms. In practice, governments found it politically difficult to allow
prices to float, especially when world oil prices rose too far. As a result, fix-
ity reforms were no more durable than price reforms. While fixity reforms
were more likely than price reforms to survive in their first year, they were
less likely to survive after 12 months. The mean duration of price reforms
was 1.8 years, while the mean duration of fixity reforms was 1.5 years.
By December 2023, when our data end, three countries still had
floating prices in place: Myanmar, which is the poorest country in our
sample; United Arab Emirates, which is the second wealthiest; and
Nigeria, which falls near the middle. We discuss these cases below.
Sources of failure
Erosion was the most common source of failure during the 2000–2023
period, bringing about the end of 47% of reforms within the first year
and 61% within 3 years. Backtracking brought about the end of 14% of
all reforms in the first year and 19% within 3 years.
0
5
10
0
01 02 03 04 05 06 07 08 09 10
11
12 13 14 15 16
17
18 19 20 21 22 23
Pre-2016 − fixity
Pre-2016 − price
Post-2016 − fixity
Post-2016 − price
a   Reform onsets, 2000–2023
0
5
10
15
0
01 02 03 04 05 06 07 08 09 10
11
12 13 14 15 16
17
18 19 20 21 22 23
Pre-2016 − fixity
Pre-2016 − price
Post-2016 − fixity
Post-2016 − price
b    Reform failures, 2000–2023
0
0.1
0.2
0.3
0.4
0.5
0.6
0.7
0.8
0.9
1.0
0
1
2
3
4
5
Years since reform onset
Survival probability
Pre-2016
Post-2016
c    Duration of reforms, pre/post-2016
0
0.1
0.2
0.3
0.4
0.5
0.6
0.7
0.8
0.9
1.0
0
1
2
3
4
5
Years since reform onset
Survival probability
Price reform
Fixity reform
d    Duration of price and fixity reforms
Fig. 1 | Incidence and duration of fuel subsidy reforms, 2000–2023. a, Change
over time in the onset of price and fixity subsidy reforms, summed across all
countries in a given year. b, Change over time in the failure of price and fixity
reforms, summed across all countries in a given year. c, Kaplan–Meier survival
rate of all subsidy reforms before (dashed orange) and after (solid blue)
December 2015. d, Kaplan–Meier survival rate of fixity (solid blue) and price
(dashed orange) subsidy reforms.
0
0.0001
0.0002
0.0003
2003 2005 2007 2009 2011
2013
2015
2017
2019
2021 2023
Backsliding
Erosion
Fig. 2 | Reform failure due to backsliding or erosion. Overlapping density plots
for backsliding and erosion over the 2000–2023 period, with the y axis showing
kernel density estimates. Backsliding refers to reversions of the nominal price to
the pre-reform nominal price. Erosion refers to reversions of the real price to pre-
reform real prices due to inflation, currency depreciation or global oil price change.

Nature Climate Change
Analysis
https://doi.org/10.1038/s41558-025-02283-4
After 2016, backtracking became more common. In the 2000–2015
period, just 9.6% of all reform failures were caused by backtracking;
after 2016, it rose to 38% of all failures (Fig. 2).
Subsidy level trends
Per-litre gasoline subsidies rose (or taxes fell) in 12 of the 21 countries
from the beginning of 2016 to December 2023. In the remaining nine,
there was little change (Table 1).
Figure 3 shows the trajectories of each country’s gasoline tax
or subsidy per litre for the full 2000–2023 period, along with the
unweighted mean. The distance above or below the horizontal line at
0.0 represents the size of the tax or subsidy. The parallel fluctuations
across the sample reflect the prevalence of price fixity, such that move-
ments are primarily due to global oil price shifts. Subsidies increased
gradually in almost all countries from 2000 to 2008. Since then, they
have fluctuated but generally remained large, except for brief periods
in 2008–2009, 2014–2015 and 2020.
Discussion
Our study finds that since 2016 there has been a rise in number of gaso-
line subsidy reforms but a decline in their durability. As a result, from
the beginning of 2016 to the end of 2023, per-litre subsidies grew for
12 countries in our sample and changed little in the other 9.
We also document a sharp rise around 2015 in fixity reforms, which
have the potential to be more far reaching and sustainable. These fixity
reforms, however, have been just as fragile as price reforms.
Despite their ambition, when push came to shove—sometimes
quite literally in the form of protests—leaders chose to restore subsi-
dies. This occurred most often through the erosion of price reforms
by devaluation or inflation, but also through backsliding that returned
prices to pre-reform levels in the face of public opposition. The price
shock that followed the Russian invasion of Ukraine was particularly
damaging, causing the reversal of fixity reforms in all but one case.
For advocates of fossil fuel subsidy reform, our results are sober-
ing. Several studies report a broad campaign to encourage fossil fuel
subsidy reforms in the mid-2010s, thanks to initiatives backed by
the Organisation for Economic Co-operation and Development, the
International Energy Agency, the World Bank, the IMF and the United
National Environmental Programme, and ultimately articulated in
section 12.c of the Sustainable Development Goals10,11. Yet, our findings
suggest that these initiatives generated little progress towards remov-
ing gasoline subsidies in the countries where reforms were needed.
The poor reform records of these 21 countries should not be entirely
surprising when taking politics into account. Recent research suggests
that fuel subsidies remain popular in many countries, where citizens
generally want to see them raised, not reduced19; that when citizens learn
that their government is providing them with large gasoline subsidies,
they tend to view the government more favourably20; that when subsidies
are removed, citizens often rise in protest7; and that successful reforms
tend to be idiosyncratic and largely driven by local, country-specific
factors16,21,22. Citizens are less likely to oppose subsidy reform if they are
given credible promises of increased public spending on health, labour
and other social outcomes23,24, yet this credibility can itself be fragile.
Although fiscally irresponsible and economically damaging, fuel
subsidies continue to have political advantages for leaders. According
to the theory of the ‘rentier state’, when undemocratic governments are
equipped with revenue derived from oil wealth-constituting ‘rents’ for
state coffers, they distribute these rents in exchange for public support
for the regime25,26. This stands in contrast with governments that lack
resource wealth and are compelled to recognize the democratic rights
of citizens in order to collect revenues from taxes.
In the early 2000s, fossil fuel subsidies became a common way for
governments to distribute oil wealth, especially when governments
lacked the administrative capacity to effectively deliver public goods
such as schools, health care and public infrastructure27. Subsidies tend
to benefit middle- and upper-class car-owning urbanites who are often a
critical source of government support28,29. Experimental evidence finds
support for tenets of this theory, demonstrating that wealthy citizens
perceive higher levels of government performance when they receive
larger fuel subsidies20.
We see two possible explanations for the simultaneous increase
in the frequency and drop in the durability of reforms since 2016. The
first is the volatility of oil prices, which can drive cycles of reform and
backsliding: falling prices can lower the barriers to reform, while rising
prices, if passed on to consumers, can ignite protests. But this expla-
nation does not fit with the evidence: oil prices were more volatile in
the 2000–2015 period than in 2016–2023 (Extended Data Fig. 9 and
Extended Data Table 1).
The other explanation is political: an increase in global pressure
for price reform may have caused governments in the Global South to
reluctantly initiate reform, even when domestic support was lacking.
This could bring about a rise in the incidence of short-lived reforms,
ended by government backsliding2. This explanation is consistent with
our finding that backsliding became much more common after 2015.
−1.0
−0.5
0
0.5
1.0
1.5
0
01
02
03
04
05
06
07
08
09
10
11
12
13
14
15
16
17
18
19
20
21
22
23
Fig. 3 | Gasoline taxes and subsidies, 2000–2023. The grey lines represent
a given country’s per-litre tax or subsidy on regular unleaded gasoline in
constant 2015 dollars. The red line represents the unweighted mean value across
countries. The sample includes all countries that maintained net subsidies from
January 2003 to December 2015. The vertical green line shows the timing of the
Paris meeting in December 2015.

Nature Climate Change
Analysis
https://doi.org/10.1038/s41558-025-02283-4
There were only three exceptions to the overall pattern of reform
failure. None of them, however, offers a straightforward model for other
countries: the United Arab Emirates has maintained fixity reforms, but
the burden of higher gasoline prices largely falls on non-citizens, who
outnumber citizens 9 to 1; Myanmar has maintained fixity reforms dur-
ing a crippling civil war and trade sanctions, while offering subsidized
gasoline to military-aligned companies30; and since May 2023, Nigeria
has adopted a mixed system of reforms and subsidies that has created
nationwide fuel shortages31,32.
Our findings underscore the extraordinary challenge of fossil fuel
subsidy reform. We see two plausible policy responses.
The first would be for advocates to redouble their efforts, look-
ing for novel strategies to build public support and guard reforms
against pressures created by inflation, currency devaluation and oil
price fluctuations.
The second would be to look for less unpopular ways to reduce
the cost of subsidies. Market pricing may be the first-best solution,
but it is often politically out of reach. Alternatively, governments
could adopt policies that reduce the demand for subsidized fuel,
for example, with regulatory measures to improve fuel efficiency,
promote electric vehicles and invest in public transit. If successful,
pro-renewables policy mixes could reduce emissions33 while foster-
ing new coalitions of political support that could ward off future
political setbacks34,35.
Online content
Any methods, additional references, Nature Portfolio reporting sum-
maries, source data, extended data, supplementary information,
acknowledgements, peer review information; details of author contri-
butions and competing interests; and statements of data and code avail-
ability are available at https://doi.org/10.1038/s41558-025-02283-4.
References
1.
Davis, L. W. The economic cost of global fuel subsidies. Am. Econ.
Rev. 104, 581–85 (2014).
2.
Rentschler, J. & Bazilian, M. Reforming fossil fuel subsidies:
drivers, barriers and the state of progress. Clim. Policy 17, 891–914
(2017).
3.
Charap, M. J., da Silva, M. A. R. & Rodriguez, M. P. C. Energy
Subsidies and Energy Consumption: A Cross-Country Analysis.
Working Paper No.13/112 (International Monetary Fund, 2013).
4.
Erickson, P. et al. Why fossil fuel producer subsidies matter.
Nature 578, E1–E4 (2020).
5.
Black, M. S., Liu, A. A., Parry, I. W. & Vernon, N. IMF Fossil Fuel
Subsidies Data: 2023 Update (International Monetary Fund,
2023).
6.
Steadman, S., Gençsü, I., Mustapha, S., Colenbrander, S. &
Tyson, J. Indebted: How to Support Countries Heavily Reliant on
Oil and Gas Revenues to Secure Long-Term Prosperity (Overseas
Development Institute, 2023).
7.
Natalini, D., Bravo, G. & Newman, E. Fuel riots: definition, evidence
and policy implications for a new type of energy-related conflict.
Energy Policy 147, 111885 (2020).
8.
von Uexkull, N., Rød, E. G. & Svensson, I. Fueling protest? Climate
change mitigation, fuel prices and protest onset. World Dev. 177,
106536 (2024).
9.
Van de Graaf, T. & Blondeel, M. in The Politics of Fossil Fuel
Subsidies and Their Reform (eds Skovgaard, J. & van Asselt, H.)
Ch. 1 (Cambridge Univ. Press, 2018).
10.	 Skovgaard, J. The Economisation of Climate Change: How the G20,
the OECD and the IMF Address Fossil Fuel Subsidies and Climate
Finance (Cambridge Univ. Press, 2021).
11.
Elliott, C., Bernstein, S. & Hoffmann, M. Credibility dilemmas
under the Paris Agreement: explaining fossil fuel subsidy reform
references in INDCs. Int. Environ. Agreem. 22, 735–759 (2022).
12.	 Sanchez, L., Wooders, P., Mostafa, M. & Bechauf, R. 53 Ways to
Reform Fossil Fuel Consumer Subsidies and Pricing (International
Institute for Sustainable Development, 2020).
13.	 Muta, T. & Erdogan, M. The Global Energy Crisis Pushed Fossil Fuel
Consumption Subsidies to an All-Time High in 2022 (International
Energy Agency, 2023).
14.	 Kojima, M. & Koplow, D. Fossil Fuel Subsidies: Approaches and
Valuation. Policy Research Working Paper 7220 (World Bank,
2015).
15.	 Ross, M. L., Hazlett, C. & Mahdavi, P. Global progress and
backsliding on gasoline taxes and subsidies. Nat. Energy 2, 16201
(2017).
16.	 Martinez-Alvarez, C. B., Hazlett, C., Mahdavi, P. & Ross, M. L.
Political leadership has limited impact on fossil fuel taxes and
subsidies. Proc. Natl Acad. Sci. USA 119, e2208024119 (2022).
17.	 Van de Graaf, T. Is OPEC dead? Oil exporters, the Paris Agreement
and the transition to a post-carbon world. Energy Res. Social Sci.
23, 182–188 (2017).
18.	 van den Bergh, J. C. & Savin, I. Political leadership, climate
policy, and renewable energy. Proc. Natl Acad. Sci. USA 120,
e2301291120 (2023).
19.	 Vieites, Y., Andretti, B., Weiss, M., Jacob, J. & Hallack, M. Effectively
communicating the removal of fossil energy subsidies: evidence
from Latin America. Glob. Environ. Change 81, 102690 (2023).
20.	 Kubinec, R. & Milner, H. V. Taxes in the time of revolution: an
experimental test of the rentier state during Algeria’s Hirak. World
Politics 76, 294–333 (2024).
21.	 Inchauste, G. & Victor, D. G. The Political Economy of Energy
Subsidy Reform (The World Bank, 2017).
22.	 Skovgaard, J. & van Asselt, H. The Politics of Fossil Fuel Subsidies
and Their Reform (Cambridge Univ. Press, 2018).
23.	 Kyle, J. Local corruption and popular support for fuel subsidy
reform in Indonesia. Comp. Polit. Stud. 51, 1472–1503 (2018).
24.	 Harring, N., Jönsson, E., Matti, S., Mundaca, G. & Jagers, S. C.
Cross-national analysis of attitudes towards fossil fuel subsidy
removal. Nat. Clim. Change 13, 244–249 (2023).
25.	 Beblawi, H. & Luciani, G. The Rentier State (Routledge, 1990).
26.	 Ross, M. L. The Oil Curse: How Petroleum Wealth Shapes the
Development of Nations (Princeton Univ. Press, 2012).
27.	 Hertog, S. The political economy of distribution in the Middle
East: is there scope for a new social contract? Dev. Policy 88,
88–113 (2017).
28.	 Bates, R. H. Markets and States in Tropical Africa: The Political Basis
of Agricultural Policies (Univ. California Press, 1981).
29.	 Kim, S. E. & Urpelainen, J. Democracy, autocracy and the urban
bias: evidence from petroleum subsidies. Polit. Stud. 64, 552–572
(2016).
30.	 Myint, M., Seong, J. & Aliyev, S. Energy Sector: Myanmar
Infrastructure Monitoring. Policy Research Working Paper 170200
(The World Bank, 2022).
31.	 Anyaogu, I. Nigerian gasoline prices soar as shortages worsen
cost of living. Reuters (2024); https://www.reuters.com/world/
africa/nigerian-gasoline-prices-soar-shortages-worsen-cost-
living-crisis-2024-04-30/
32.	 Nigeria: Post-financing Assessment Discussions (International
Monetary Fund, 2024).
33.	 Axsen, J., Plötz, P. & Wolinetz, M. Crafting strong, integrated
policy mixes for deep CO2 mitigation in road transport. Nat. Clim.
Change 10, 809–818 (2020).
34.	 Breetz, H., Mildenberger, M. & Stokes, L. The political logics of
clean energy transitions. Bus. Politics 20, 492–522 (2018).
35.	 Beiser-McGrath, L. F., Bernauer, T. & Prakash, A. Command and
control or market-based instruments? Public support for policies
to address vehicular pollution in Beijing and New Delhi. Environ.
Politics 32, 586–618 (2023).

Nature Climate Change
Analysis
https://doi.org/10.1038/s41558-025-02283-4
Publisher’s note Springer Nature remains neutral with
regard to jurisdictional claims in published maps and
institutional affiliations.
Springer Nature or its licensor (e.g. a society or other partner) holds
exclusive rights to this article under a publishing agreement with
the author(s) or other rightsholder(s); author self-archiving of the
accepted manuscript version of this article is solely governed by the
terms of such publishing agreement and applicable law.
© The Author(s), under exclusive licence to Springer Nature Limited
2025

Nature Climate Change
Analysis
https://doi.org/10.1038/s41558-025-02283-4
Methods
Measurement of fuel subsidies
Most research on fossil fuel subsidies is concerned with estimating the
damages they cause and the benefits of subsidy reform1,2,36. Our study
builds on two smaller bodies of positive research.
The first is made up of cross-national quantitative studies of gaso-
line taxes and subsidies—the most readily measured type of fossil fuel
subsidy. In general, these studies demonstrate that gasoline taxes
and subsidies are closely associated with slowly changing economic
factors, especially income per capita and fossil fuel wealth. The role of
politics is more uncertain: some studies find a link between fuel taxes
and political institutions29,37,38, whereas others do not39.
These studies have important limitations: they only cover the
period until 2015 or 2016; they look simultaneously at taxes and subsi-
dies, and generally make no distinction between the political challenges
of raising taxes and the political challenges of removing subsidies; and
they cannot make strong claims about causal effects.
The second set consists of qualitative case studies, which offer
in-depth analyses of specific instances of reform12,21,22,40. While their
emphases vary, in general they suggest that success is more likely to
follow a well-designed communications strategy, targeted compen-
sation for affected communities and a gradual, phased approach to
implementation2. One advantage of these studies is their capacity to
cover many types of fossil fuel subsidies and describe more subtle,
context-specific influences. Their disadvantages include a tendency to
focus on cases of success (that is, selection on the dependent variable)
and less attention to the durability of reforms.
Our analysis has several innovations. It is the first quantitative
analysis to cover the post-Paris period, allowing us to provide an
upper-bound estimate of Paris’s effects; it measures both the inci-
dence of reforms and their duration; it distinguishes between price
reforms and fixity reforms, charting the growing popularity (but lim-
ited success) of the latter; and it offers a more detailed analysis of how
reforms fail.
Measurement approach
Most countries tax the consumption of fossil fuels rather than sub-
sidize it. Among those that subsidize, some target their subsidies
towards low-income, vulnerable populations and use them for rela-
tively brief periods; others subsidize most or all of their citizens over
many years. Our study is concerned with the latter group of countries,
which are typically the focus of international efforts to reduce fossil
fuel subsidies.
We follow convention and define a subsidy as the difference
between the price paid by consumers and the cost of bringing the fuel
to market14. To measure the size of these subsidies, we use the price
gap method, which compares the observed retail price of a fuel in each
country with a global benchmark price, which represents the supply
cost. Anytime the retail price falls below the benchmark price (for exam-
ple, the cost of supplying the fuel), it denotes a subsidy for that period.
To identify the countries that were net subsidizers in the pre Paris
era, we use the ref. 15 dataset of monthly gasoline taxes and subsidies,
which covers 157 countries. We include in the sample all countries
whose median gasoline price for the 2003–2015 period was below
the median benchmark for the same period, meaning they were net
subsidizers during this initial period. This yields 22 countries, one of
which (Yemen) we drop due to missing data in the period after its civil
war began.
Data and sample
We used a combination of government documents, oil and gas industry
reporting, and media reports to extend the original 2000–2015 data to
December 2023 for our sample. Data are missing for 173 of the 8,568
country-months owing to periods of political disruption for Myanmar
and Venezuela.
The countries in our sample are located in different regions—Latin
America, the Middle East, North Africa, Central Asia, Sub-Saharan Africa
and Southeast Asia—yet share two important characteristics: they are
exporters of oil or fossil gas; and they tend to set fuel prices by govern-
ment fiat, protecting them from global price fluctuations. The use of
fixed gasoline prices creates a link between the global oil price and the
size of the subsidy: when global prices rise, so do the benefits accruing
to local consumers who continue to enjoy the fixed price and, hence,
are receiving a larger per-unit subsidy.
Subsidy reforms
We analyse two varieties of subsidy reform. The most common type is
price reform, when a country raises the nominal price by 10% or more in
local currency units in a single month. For robustness, we use an alter-
native measure of price reform, when governments raise the nominal
price by 25% or more over a 3-month period. Among the 21 countries
in our sample, all but one (Oman) initiated at least one episode of price
reform between 2000 and 2023. Three countries (Iran, Sudan and
Angola) had ten or more price reforms (Extended Data Fig. 3 and 4).
Price reform ends (or fails) if the subsidy returns to its pre-
reform level, which can happen through two mechanisms: the gov-
ernment may lower the nominal price to its pre-reform level, the
process we call backtracking; or the government may maintain the
post-reform price, but its value disappears through inflation, a fall-
ing exchange rate or rising global oil prices. We refer to the latter
process as erosion.
The second type is fixity reform, which occurs when a government
stops using fixed prices and subsidies altogether, allowing gasoline
prices to fluctuate in response to changing oil prices for at least three
consecutive months. A fixity reform can fail in two ways: the ‘fixity’
component can fail if the government reimposes fixed prices for three
or more consecutive months; or the ‘no subsidies’ component can
fail if the government interferes with the market price to restore a
substantial subsidy (which we define as a subsidy exceeding 20 cents
per litre in constant 2015 US dollars for three consecutive months).
All 21 countries had government-fixed gasoline prices for most of the
2000–2023 period, but ten of them shifted one or more times to float-
ing prices (Extended Data Fig. 2).
In Extended Data Fig. 1, we illustrate our measures using the case
of Nigeria.
Data availability
The fossil fuel subsidy data supporting the findings of this study are
available via the Harvard DataVerse at https://dataverse.harvard.edu/
dataset.xhtml?persistentId=doi:10.7910/DVN/80JO6T.
Code availability
The code to replicate all findings of this study is available via Code
Ocean at https://doi.org/10.24433/CO.8539725.v1.
References
36.	 Parry, I., Black, M. S. & Vernon, N. Still Not Getting Energy Prices
Right: A Global and Country Update of Fossil Fuel Subsidies
(International Monetary Fund, 2021).
37.	 Cheon, A., Urpelainen, J. & Lackner, M. Why do governments
subsidize gasoline consumption? An empirical analysis of
global gasoline prices, 2002–2009. Energy Policy 56, 382–390
(2013).
38.	 Fails, M. D. What types of political regimes subsidize fuel
consumption? Extr. Ind. Soc. 9, 101037 (2022).
39.	 Mahdavi, P., Martinez-Alvarez, C. B. & Ross, M. L. Why do govern
ments tax or subsidize fossil fuels? J. Politics https://doi.org/10.1086/
719272 (2022).
40.	 Clements, B. J. et al. Energy Subsidy Reform: Lessons and
Implications (International Monetary Fund, 2013).

Nature Climate Change
Analysis
https://doi.org/10.1038/s41558-025-02283-4
Acknowledgements
We thank J. Cameron for her valuable research assistance.
We received helpful feedback following presentations at
the University of California Santa Barbara, the University of
California Berkeley, the University of Notre Dame, the US Agency
for International Development, the 2023 annual meeting
of the American Political Science Association and the 2023
meeting of the International Political Science Association in
Buenos Aires.
Author contributions
P.M. and M.L.R. conceptualized the study and oversaw data
collection. E.S. performed the data analysis and interpretation of the
results. M.L.R. led the manuscript writing. All authors contributed
equally to reviewing and editing the manuscript and approved the
final version.
Competing interests
The authors declare no competing interests.
Additional information
Extended data is available for this paper at
https://doi.org/10.1038/s41558-025-02283-4.
Correspondence and requests for materials should be addressed to
Paasha Mahdavi or Michael L. Ross.
Peer review information Nature Climate Change thanks
Federica Genovese, Jakob Skovgaard and Thijs Van de Graaf for their
contribution to the peer review of this work.
Reprints and permissions information is available at
www.nature.com/reprints.

Nature Climate Change
Analysis
https://doi.org/10.1038/s41558-025-02283-4
0
200
400
600
00
02
04
06
08
10
12
14
16
18
20
22
0.2
0.4
0.6
0.8
00
02
04
06
08
10
12
14
16
18
20
22
0.4
0.6
0.8
00
02
04
06
08
10
12
14
16
18
20
22
−0.50
−0.25
0.00
0.25
00
02
04
06
08
10
12
14
16
18
20
22
00
02
04
06
08
10
12
14
16
18
20
22
00
02
04
06
08
10
12
14
16
18
20
22
Extended Data Fig. 1 | Combined figures of the case of Nigeria. Panels a, b, and
c show the price paid by consumers over time. a, The price in current Nigerian
Naira. b, The price denominated in current US dollars, which reveals the effects
of changes in the value of the currency. c, The price in constant 2015 US dollars,
which accounts for the additional effects of inflation. d, The value of the per-liter
implicit tax or subsidy measured with the price-gap method. e, The onset of
price reforms. f, The periods of fixity reform for which Nigeria implemented
floating prices.

Nature Climate Change
Analysis
https://doi.org/10.1038/s41558-025-02283-4
Extended Data Fig. 2 | Periods of Fixity Reform.

Nature Climate Change
Analysis
https://doi.org/10.1038/s41558-025-02283-4
Extended Data Fig. 3 | Increases of Monthly Prices Above 10 percent.

Nature Climate Change
Analysis
https://doi.org/10.1038/s41558-025-02283-4
Extended Data Fig. 4 | Increases of Quarterly Prices Above 25 percent.

Nature Climate Change
Analysis
https://doi.org/10.1038/s41558-025-02283-4
Extended Data Fig. 5 | Survival Estimates for Price Reform 25 percent, 2000-2015 vs 2016-2023.

Nature Climate Change
Analysis
https://doi.org/10.1038/s41558-025-02283-4
Extended Data Fig. 6 | Sensitivity Analysis: Kaplan-Meier survival rate of all subsidy reforms before (dashed orange) and after (solid blue) December 2014.

Nature Climate Change
Analysis
https://doi.org/10.1038/s41558-025-02283-4
Extended Data Fig. 7 | Leave Out Analysis. Pre and Post 2016.
0.0
0.1
0.2
0.3
0.4
0.5
0.6
0.7
0.8
0.9
1.0
0
1
2
3
4
5
Years since Reform Onset
Survival Probability
Pre Paris
Post Paris
0.0
0.1
0.2
0.3
0.4
0.5
0.6
0.7
0.8
0.9
1.0
0
1
2
3
4
5
Years since Reform Onset
Survival Probability
Pre Paris
Post Paris
0.0
0.1
0.2
0.3
0.4
0.5
0.6
0.7
0.8
0.9
1.0
0
1
2
3
4
5
Years since Reform Onset
Survival Probability
Pre Paris
Post Paris
0.0
0.1
0.2
0.3
0.4
0.5
0.6
0.7
0.8
0.9
1.0
0
1
2
3
4
5
Years since Reform Onset
Survival Probability
Pre Paris
Post Paris
0.0
0.1
0.2
0.3
0.4
0.5
0.6
0.7
0.8
0.9
1.0
0
1
2
3
4
5
Years since Reform Onset
Survival Probability
Pre Paris
Post Paris
0.0
0.1
0.2
0.3
0.4
0.5
0.6
0.7
0.8
0.9
1.0
0
1
2
3
4
5
Years since Reform Onset
Survival Probability
Pre Paris
Post Paris
0.0
0.1
0.2
0.3
0.4
0.5
0.6
0.7
0.8
0.9
1.0
0
1
2
3
4
5
Years since Reform Onset
Survival Probability
Pre Paris
Post Paris
0.0
0.1
0.2
0.3
0.4
0.5
0.6
0.7
0.8
0.9
1.0
0
1
2
3
4
5
Years since Reform Onset
Survival Probability
Pre Paris
Post Paris
0.0
0.1
0.2
0.3
0.4
0.5
0.6
0.7
0.8
0.9
1.0
0
1
2
3
4
5
Years since Reform Onset
Survival Probability
Pre Paris
Post Paris
0.0
0.1
0.2
0.3
0.4
0.5
0.6
0.7
0.8
0.9
1.0
0
1
2
3
4
5
Years since Reform Onset
Survival Probability
Pre Paris
Post Paris
0.0
0.1
0.2
0.3
0.4
0.5
0.6
0.7
0.8
0.9
1.0
0
1
2
3
4
5
Years since Reform Onset
Survival Probability
Pre Paris
Post Paris
0.0
0.1
0.2
0.3
0.4
0.5
0.6
0.7
0.8
0.9
1.0
0
1
2
3
4
5
Years since Reform Onset
Survival Probability
Pre Paris
Post Paris
0.0
0.1
0.2
0.3
0.4
0.5
0.6
0.7
0.8
0.9
1.0
0
1
2
3
4
5
Years since Reform Onset
Survival Probability
Pre Paris
Post Paris
0.0
0.1
0.2
0.3
0.4
0.5
0.6
0.7
0.8
0.9
1.0
0
1
2
3
4
5
Years since Reform Onset
Survival Probability
Pre Paris
Post Paris
0.0
0.1
0.2
0.3
0.4
0.5
0.6
0.7
0.8
0.9
1.0
0
1
2
3
4
5
Years since Reform Onset
Survival Probability
Pre Paris
Post Paris
0.0
0.1
0.2
0.3
0.4
0.5
0.6
0.7
0.8
0.9
1.0
0
1
2
3
4
5
Years since Reform Onset
Survival Probability
Pre Paris
Post Paris
0.0
0.1
0.2
0.3
0.4
0.5
0.6
0.7
0.8
0.9
1.0
0
1
2
3
4
5
Years since Reform Onset
Survival Probability
Pre Paris
Post Paris
0.0
0.1
0.2
0.3
0.4
0.5
0.6
0.7
0.8
0.9
1.0
0
1
2
3
4
5
Years since Reform Onset
Survival Probability
Pre Paris
Post Paris
0.0
0.1
0.2
0.3
0.4
0.5
0.6
0.7
0.8
0.9
1.0
0
1
2
3
4
5
Years since Reform Onset
Survival Probability
Pre Paris
Post Paris
0.0
0.1
0.2
0.3
0.4
0.5
0.6
0.7
0.8
0.9
1.0
0
1
2
3
4
5
Years since Reform Onset
Survival Probability
Pre Paris
Post Paris
0.0
0.1
0.2
0.3
0.4
0.5
0.6
0.7
0.8
0.9
1.0
0
1
2
3
4
5
Years since Reform Onset
Survival Probability
Pre Paris
Post Paris

Nature Climate Change
Analysis
https://doi.org/10.1038/s41558-025-02283-4
Extended Data Fig. 8 | Leave Out Analysis. Fixity versus Price Reforms.
0.0
0.1
0.2
0.3
0.4
0.5
0.6
0.7
0.8
0.9
1.0
0
1
2
3
4
5
Years since Reform Onset
Survival Probability
Price Reform
Fixity Reform
0.0
0.1
0.2
0.3
0.4
0.5
0.6
0.7
0.8
0.9
1.0
0
1
2
3
4
5
Years since Reform Onset
Survival Probability
Price Reform
Fixity Reform
0.0
0.1
0.2
0.3
0.4
0.5
0.6
0.7
0.8
0.9
1.0
0
1
2
3
4
5
Years since Reform Onset
Survival Probability
Price Reform
Fixity Reform
0.0
0.1
0.2
0.3
0.4
0.5
0.6
0.7
0.8
0.9
1.0
0
1
2
3
4
5
Years since Reform Onset
Survival Probability
Price Reform
Fixity Reform
0.0
0.1
0.2
0.3
0.4
0.5
0.6
0.7
0.8
0.9
1.0
0
1
2
3
4
5
Years since Reform Onset
Survival Probability
Price Reform
Fixity Reform
0.0
0.1
0.2
0.3
0.4
0.5
0.6
0.7
0.8
0.9
1.0
0
1
2
3
4
5
Years since Reform Onset
Survival Probability
Price Reform
Fixity Reform
0.0
0.1
0.2
0.3
0.4
0.5
0.6
0.7
0.8
0.9
1.0
0
1
2
3
4
5
Years since Reform Onset
Survival Probability
Price Reform
Fixity Reform
0.0
0.1
0.2
0.3
0.4
0.5
0.6
0.7
0.8
0.9
1.0
0
1
2
3
4
5
Years since Reform Onset
Survival Probability
Price Reform
Fixity Reform
0.0
0.1
0.2
0.3
0.4
0.5
0.6
0.7
0.8
0.9
1.0
0
1
2
3
4
5
Years since Reform Onset
Survival Probability
Price Reform
Fixity Reform
0.0
0.1
0.2
0.3
0.4
0.5
0.6
0.7
0.8
0.9
1.0
0
1
2
3
4
5
Years since Reform Onset
Survival Probability
Price Reform
Fixity Reform
0.0
0.1
0.2
0.3
0.4
0.5
0.6
0.7
0.8
0.9
1.0
0
1
2
3
4
5
Years since Reform Onset
Survival Probability
Price Reform
Fixity Reform
0.0
0.1
0.2
0.3
0.4
0.5
0.6
0.7
0.8
0.9
1.0
0
1
2
3
4
5
Years since Reform Onset
Survival Probability
Price Reform
Fixity Reform
0.0
0.1
0.2
0.3
0.4
0.5
0.6
0.7
0.8
0.9
1.0
0
1
2
3
4
5
Years since Reform Onset
Survival Probability
Price Reform
Fixity Reform
0.0
0.1
0.2
0.3
0.4
0.5
0.6
0.7
0.8
0.9
1.0
0
1
2
3
4
5
Years since Reform Onset
Survival Probability
Price Reform
Fixity Reform
0.0
0.1
0.2
0.3
0.4
0.5
0.6
0.7
0.8
0.9
1.0
0
1
2
3
4
5
Years since Reform Onset
Survival Probability
Price Reform
Fixity Reform
0.0
0.1
0.2
0.3
0.4
0.5
0.6
0.7
0.8
0.9
1.0
0
1
2
3
4
5
Years since Reform Onset
Survival Probability
Price Reform
Fixity Reform
0.0
0.1
0.2
0.3
0.4
0.5
0.6
0.7
0.8
0.9
1.0
0
1
2
3
4
5
Years since Reform Onset
Survival Probability
Price Reform
Fixity Reform
0.0
0.1
0.2
0.3
0.4
0.5
0.6
0.7
0.8
0.9
1.0
0
1
2
3
4
5
Years since Reform Onset
Survival Probability
Price Reform
Fixity Reform
0.0
0.1
0.2
0.3
0.4
0.5
0.6
0.7
0.8
0.9
1.0
0
1
2
3
4
5
Years since Reform Onset
Survival Probability
Price Reform
Fixity Reform
0.0
0.1
0.2
0.3
0.4
0.5
0.6
0.7
0.8
0.9
1.0
0
1
2
3
4
5
Years since Reform Onset
Survival Probability
Price Reform
Fixity Reform
0.0
0.1
0.2
0.3
0.4
0.5
0.6
0.7
0.8
0.9
1.0
0
1
2
3
4
5
Years since Reform Onset
Survival Probability
Price Reform
Fixity Reform

Nature Climate Change
Analysis
https://doi.org/10.1038/s41558-025-02283-4
Extended Data Fig. 9 | Daily oil price volatility, 2000-2023. Data from the U.S. Energy Information Administration: ‘Europe Brent Spot Price FOB’.

Nature Climate Change
Analysis
https://doi.org/10.1038/s41558-025-02283-4
Extended Data Table 1 | Comparison of Oil Volatility in 2000-2015 versus 2016-2023

    Scientific Research Study Methods:

Answer: Our sample consists of monthly gasoline prices from 2000 to 2023 of the 21 countries that maintained substantial gasoline subsidies during the pre-2015 period. Together, they accounted for 97% of all gasoline subsidies between 2003 and 2015. All were oil and gas producers. We collected new data on their gasoline prices by using government documents, industry records and media reports. We then applied the price-gap method to calculate monthly subsidies from January 2016 to December 2023. This enabled us to identify both price reforms, meaning one-time increases in the local gasoline price, and fixity reforms, meaning a shift from fixed prices set by the government to floating, market-based prices. We tabulated both the incidence of reforms in each country and how long each reform lasted. If it failed, we recorded the reasons why.