Open Journal of Political Science
2013. Vol.3, No.1, 39-43
Published Online January 2013 in SciRes (http://www.scirp.org/journal/ojps) http://dx.doi.org/10.4236/ojps.2013.31006
Influences on Adoption of Greenhouse Gas Reduction
Targets among US States, 1998-2008
Tabitha M. Cale1, Margaret A. Reams2
1Department of Political Science, Louisiana State University, Baton Rouge, USA
2Department of Environmental Sciences, Louisiana State University, Baton Rouge, USA
Received October 7th, 2012; revised November 17th, 2012; accepted November 29th, 2012
While the United States has not established federal regulations for greenhouse gas (GHG) reduction tar-
gets, many US states have adopted their own standards and guidelines. In this study we examine state
adoption of targets for GHG reductions during the ten-year period of 1998-2008, and identify factors that
explain variation in target adoption. Potential influences are drawn from research from the public policy
formulation and diffusion literature, and from studies specific to climate policy adoption. Potential influ-
ences on GHG reduction efforts among US states include socioeconomic attributes of residents, political
and ideological orientations of citizens and state government, interest group activities, environmental
pressures, and proximity to other states that have adopted GHG reduction targets. The findings of the
multinomial logistic regression analysis indicate that states are more likely to adopt GHG reduction tar-
gets if they share a border with another state with a similar climate program and if their citizens are more
ideologically liberal. Other factors including socioeconomic resources and interest group activities were
not found to be associated with policy adoption. The findings yield insights into the conditions under
which states are more likely to take action to reduce GHG’s, and are relevant both to state policy makers
and residents with an interest in climate planning, and for researchers attempting to estimate future green-
house gas reduction scenarios.
Keywords: Climate Change Policy; State Climate Planning; Greenhouse Gases (GHG’s); State
Environmental Policy
Introduction
The 1997 Kyoto Protocol was not ratified by the US Senate
and, to date, no federal targets for greenhouse gas (GHG) re-
ductions have been set. In this context, many states have been
proactive in establishing their own GHG reduction targets. The
potential greenhouse gas (GHG) reductions from state actions
are significant. Lutsey and Sperling (2008) calculated that if all
of the state and city emissions targets in place were to be achie-
ved, US GHG emissions could be stabilized at 2010 levels as
soon as 2020. This would be a substantial reduction in GHG’s
and could be accomplished without federal mandates.
Adoption of climate-change mitigation policies is a complex
challenge for state and federal policy makers for several rea-
sons. As W. Neil Adger (2009) pointed out, the scale and in-
terconnectedness of the impacts of climate change are growing
each year, so that “the window to act” may be shorter than we
realize. Despite a possible sense of urgency, it is difficult to
conduct cost-benefit type analyses of various mitigation strate-
gies because the precise extent and timing of future damages
are difficult to determine. As a result, the future benefits to be
gained through mitigation programs are difficult to quantify
fully, while the present-day costs of some of the options, in-
cluding implementing specific GHG reduction targets, are eas-
ier to determine. In this context, it can be hard to summon the
political will necessary to address climate change mitigation,
especially given the existence of other compelling public prob-
lems competing for limited public resources.
Also, climate change planning is made more difficult by a
tendency among policy makers in the US to display a “short-
term bias” in decision making. Consideration of problems and
associated damages likely to occur more than four years in the
future tend to be differed to later administrations, while more
pressing issues are considered and acted upon in the present
(Vig & Kraft, 2010).
Given these challenges and disincentives, why have some US
states taken steps to address climate change while others have
not? In this paper we examine the adoption of GHG reduction
targets among US states during the ten year period after Kyoto,
from 1998 to 2008. Our central research objective is to identify
key factors that may explain variation in state officials’ deci-
sions to adopt state-level GHG reduction targets.
Related Research
In order to identify potential influences on state actions, we
consider several themes within the political science public pol-
icy literature. First, researchers have examined patterns of pol-
icy “diffusion” among states within a geographic region and
from one level of government to another. This “policy learning”
and diffusion literature has examined “horizontal” diffusion of
policy across the same level of government (Volden, 2006;
Berry & Baybeck, 2005; Berry & Berry, 1990; Mooney & Lee,
1995) as well as “vertical” diffusion of policy between different
levels of government (Shipan & Volden 2006). Studies of hori-
zontal policy diffusion generally have concluded that policies

T. M. CALE, M. A. REAMS
“seem to spread between states that share a region and between
states that share borders”. (Ingle et al., 2007: p. 607).
Other researchers have turned to factors within the state or
“internal determinants” as key influences on officials’ decisions
to adopt certain policies (Gray, 1973, 1994; Fredriksson & Mil-
limet, 2002). This orientation is reflected in Ingle and collea-
gues’ statement that “states adopt politics only when their own
political, economic, and social environments are favorable”
(Ingle et al., 2007: p. 607).
Of course, diffusion across state or regional borders is not
mutually exclusive with the view that state policy adoption also
is influenced by contextual factors within each state. So, re-
cently, a third approach to understanding policy diffusion has
emerged, combining elements of the diffusion literature and
elements of the internal determinants literature; policies may
spread across states with similar political party identifications
and other internal characteristics and need not necessarily share
a border or be in the same region as a state that is being emu-
lated (Gray & Hanson, 2008). For example, Volden found that
“similarities based on ideological leanings, per-capita income…
and budgetary considerations” were all significantly related to
policy diffusion (Volden, 2006: p. 310).
A second broad theme examines potential linkages between
environmental policy adoption and the level of enforcement of
existing environmental regulations. Woods (2006) argues that
environmental regulation is particularly susceptible to a “race to
the bottom” scenario since negative externalities of pollution
could be left to other jurisdictions to address, while the nearby
state with the least regulation could benefit economically. In
other words, states could have an incentive to avoid adopting
strict regulatory standards, in order to attract polluting Indus-
tries and thereby gain a competitive economic advantage (Ring-
quist, 1993).
Woods notes that there is “little evidence that firms relocate
on the basis of regulatory cost differentials” but that “survey
evidence suggests that regulators believe they do and that this
belief appears to affect environmental policy” (Woods, 2006: p.
177). This apparent paradox may exist either because policy-
makers are unaware of all factors involved in a decision for a
given firm to relocate, or because regulators are under pressure
from industry lobbyists to regulate as little as possible, even
when firms have no intention of relocating.
In an examination of EPA data on the enforcement of federal
pollution laws, Konisky (2007) concludes that states respond to
the regulatory behavior of others states, but those responses
tend to vary. Whereas some states would respond to the more
stringent regulatory stance of neighboring states, for example,
and “race to the top”, actually strengthening their environmen-
tal standard and regulations, others may tend to maintain less
stringent standards.
In addition to these potential influences on state GHG reduc-
tion efforts, the political and ideological perspectives of citizens
and policy makers concerning climate change may be espe-
cially relevant (McCright & Dunlap 2003). The Pew Research
Center for the People and The Press, in a survey conducted
April 23-27, 2008, found a significant partisan divide between
Republicans and Democrats concerning attitudes toward cli-
mate change. When asked if there is “solid evidence of global
warming” 84% of Democrats and 75% of Independents agreed,
as compared to only 49% of Republican respondents. Democ-
rats and Independents (58% and 50% respectively) also were
more likely to believe that global warming is anthropogenic
caused by human activity, than Republicans (27%). When re-
spondents were categorized into college graduates and non-
college graduates, the partisan divide became even larger.
Asked if “global warming is happening because of human ac-
tivity”, 31% of Republicans who did not graduate from college
agreed as compared to 19% of those who did graduate from
college. Fifty-two percent of Democrats who did not graduate
from college agreed as compared to 75% of those who did, and
48 percent of Independents who did not graduate from college,
and 57% of those who did, agreed that global warming is oc-
curring as a result of human activity.
Research Questions
In light of findings and insights from these studies, we pose
several research questions.
Question 1: Are states that share a border with one or more
other states with GHG reduction targets more likely to adopt
their own GHG reduction targets?
In addition we want to examine possible “internal determi-
nants” of state adoption GHG reduction targets. We are par-
ticularly interested in whether the differences in opinions con-
cerning the causes and consequences of climate change be-
tween Democrats and Republicans may carry over into state
efforts to limit GHG’s.
Question 2: Are states with liberal citizens and/or govern-
ments more likely to adopt GHG Reduction Targets?
Additional internal attributes or conditions such as socio-
economic and environmental conditions should be examined as
well. Thus, we pose the following questions:
Question 3: Are states with higher levels of poverty less
likely to adopt GHG Reduction Targets?
Question 4: Are states with higher levels of toxic releases
less likely to adopt GHG Reduction Targets?
Also, the possible influence of a “race to the bottom (or top)”
motivation should be explored. Specifically the combination of
a state’s industrial pollution level and the climate policy actions
of neighboring states may be a relevant consideration. Thus,
Question 5: Are those states that have lower levels of toxic
releases, and also share a border with a state with GHG reduc-
tion targets, more likely to adopt GHG Reduction Targets?
A final set of potential influences include interest group ac-
tivities within each state. Setting targets for GHG emissions
could affect a range of economic interests including those in-
volved in energy production and delivery, building and con-
struction, and infrastructure and transportation planning. Given
that these interests may be competing with environmental
groups for influence in the establishment of new climate poli-
cies, it is useful to examine potential associations between po-
litical donations from major interest groups and state adoption
of GHG reduction standards. We assume that environmental
interest groups would be more likely to support climate change
policies, in general, and traditional energy interests (oil and gas
industry) may be hesitant to accept increased regulation con-
cerning GHG’s. Thus, we pose the following questions:
Question 6: Are states with higher levels of political contri-
butions from environmental and alternative energy interest
groups more likely to adopt GHG Reduction Targets? , and;
Question 7: Are states with higher levels of political contri-
butions from traditional energy interest groups less likely to
adopt GHG Reduction Targets?
40

T. M. CALE, M. A. REAMS
Data and Methods
The analysis uses panel, cross-sectional data to examine state
adoption of GHG reduction targets from 1998-2008. The de-
pendent variable in this analysis is whether a state had GHG
reduction targets in place during each year of the ten-year time
frame. Data to construct the dependent variable came from the
Pew Center on Global Climate Change. The variable is coded
as “0” (zero) in years the state had not adopted GHG targets,
and “1” (one) for years in which targets were present. The ten-
year period was selected because it was a time of heightened
public debate concerning climate change, including the 1997
Kyoto Protocol, the US Senate’s subsequent vote not to ratify
the treaty, and the release of the influential film, An Inconven-
ient Truth.
The independent variables include one indicator of possible
“horizontal policy diffusion” or the spreading of the GHG re-
duction target policy between states with shared borders. We
constructed the variable “Border State” using information pro-
vided by the Pew Climate organization. The variable was coded
“0” if no bordering state had a GHG reduction target within the
year, and coded “1” if at least one bordering state had targets in
place that year. Concerning the internal characteristics of the
state, the variables “Liberal Government” and “Liberal Citi-
zens”, were included. These variables were constructed by
Berry et al. in 1996 and have been updated annually.
The variable Toxic Release Inventory (TRI) releases was
gathered from the EPA for each year, as a measure of environ-
mental pollution from regulated manufacturing industries with-
in each state. We included the percentage of citizens below the
federal poverty level as an indicator of economic conditions
within the state. The variable “Poverty” was taken from the US
Census for the year 2005. Contributions from environmental
and alternative energy groups to state political parties and can-
didates (“Environmental Interest”) and contributions from tra-
ditional oil and gas energy groups (“Energy Interest”) were
compiled using data from the Followthemoney.org website. All
of the independent variables with the exception of “Poverty”
were compiled for each year from 1998-2008.
The data were analyzed using a multinomial logistic regres-
sion analysis using SPSS version 15.0. The logistic model is an
appropriate method to determine the relative associations of
each of the independent variables with the dichotomous de-
pendent variable
Results and Discussion
Seventeen states had adopted GHG reduction targets by 2008,
with California being the first state to formulate specific targets.
Thirty-three US states had not adopted reduction targets. The
17 states with GHG reduction targets are listed in alphabetical
order:
Arizona, California, Connecticut, Florida, Hawaii, Illinois,
Maine, Massachusetts, Minnesota, New Hampshire, New Jer-
sey, New Mexico, New York, Oregon, Rhode Island, Vermont
and Washington.
The logistic model yielded several interesting results con-
cerning the relative associations between the independent vari-
ables and states’ adoption of the GHG reduction targets. The
variables most significantly associated with the policy action
are “Border State”, “Liberal Citizens,” and the interaction or
combination of “Low Toxin” and “Border State” variables. The
results of the analysis are summarized below in Table 1.
Question 1: Are states that share a border with one or more
other states with GHG reduction targets more likely to adopt
their own GHG reduction targets? Yes, the results indicate that
neighboring states tend to adopt similar reduction efforts. This
finding lends support to the horizontal policy diffusion expla-
nation that public policies across a variety of issue areas are
likely to be picked up and implemented by policy makers in
neighboring states, consistent with earlier findings by Gray
(1973, 1994) and Turner and Cassel (2007). This finding offers
evidence that the process of formulating and implementing
climate change policies at the state level is similar to and influ-
enced by the same forces and influences that drive policy diffu-
sion in other subject areas.
Question 2: Are states with more liberal citizens and gov-
ernments more likely to adopt GHG reduction targets? Yes, to
some extent the findings support this linkage. The results indi-
cate that states with more liberal citizens are much more likely
to have adopted GHG reduction targets. The liberal government
variable was not found to be significantly associated with the
targets, however. The findings suggest that the extreme partisan
divisions in opinions concerning climate change documented
by the Pew research group and Berry et al. (1998) probably
have affected state adoption of GHG reduction targets, with
states with more liberal citizens being much more likely to at-
tempt to mitigate climate change.
Question 3: Are states with higher levels of poverty less
likely to adopt GHG reduction targets? No, the findings do not
offer evidence that states with larger numbers of economically
disadvantaged citizens were less able or willing to set GHG
reduction targets from 1998-2008. We included this variable to
examine whether policy makers in states where poverty is more
of a problem may be reluctant to introduce climate change
mitigation programs because the efforts may be perceived as
imposing regulatory costs that may affect private sector em-
ployment. However, the findings indicate no such reluctance on
the part of officials in states with higher poverty rates. The
results suggest that poverty within a state may not introduce
significant obstacles to GHG reduction efforts.
Question 4: Are states with higher levels of toxic releases
less likely to adopt GHG reduction targets? No, the analysis
yielded no evidence that levels of toxic releases, on their own,
Table 1.
Logistic analysis results: State adoption of greenhouse gas targets.
Coefficient SE (Robust)
Border State [+] 1.0221 0.4781*
Liberal Government [+] 0.0118 0.0094
Liberal Citizens [+] 0.0674 0.0202***
Toxic Releases [−] 0.0646 0.7323
Poverty [−] 0.0180 0.0792
Environmental Interest [+] 0.1777 0.1458
Energy Interest [−] 0.0066 0.0393
Low Toxin B or der [+] 3.4558 1.0667***
Constant −7.0661 1.5608***
Note: N = 537 (State-years); Prob > chi2 = 0.0000; Pseudo R2 = 0.5509; ***p <
0.001, **p < 0.01, *p < 0.05 (one-tailed tests).

T. M. CALE, M. A. REAMS
are related to adoption of GHG reduction targets. In other
words states with more industrial manufacturing activity that
results in higher levels of toxic emissions are not any less likely
to develop GHG reduction targets.
Question 5: Are those states that have lower levels of toxic
releases, and also share a border with a state with GHG reduc-
tion targets, more likely to adopt GHG reduction targets? Yes,
the interaction or combination of lower TRI emissions and the
presence of a border state with a GHG a reduction target pro-
gram, was found to be significantly associated with adoption of
reduction targets. States with low levels of toxic emissions may
be influenced by the GHG reduction actions of neighboring
states. This finding offers some evidence of a “race to the top”
influence among states with lower levels of toxic emissions
from regulated manufacturing industries.
Question 6: Are states with higher levels of political contri-
butions from environmental and alternative energy interest
groups more likely to adopt GHG reduction targets? and,
Question 7: Are states with higher levels of contributions to
state legislators from traditional energy interest groups less
likely to adopt GHG reduction targets?
Neither environmental interest group contributions, nor en-
ergy interest group contributions had a significant effect on
state adoption of GHG targets. One explanation for this finding
is that lobbyists for traditional oil and gas enterprises and those
representing alternative energy companies, may be engaged in
issues other than whether a state adopts GHG reduction targets.
Also, these interest groups’ positions on GHG reduction efforts
may not be as polarized as the general view of average citizens
concerning climate change. Finally, while setting GHG reduc-
tion targets may be viewed as a first step in addressing climate
change, these programs may not introduce onerous measures
that would be resisted by oil and gas energy interests at this
time. In fact “no regrets” policies and actions, such as those that
require or encourage greater energy efficiency, can introduce
benefits in addition to reduced GHG levels, and may enjoy
more widespread support among various interest groups. Addi-
tional information about the stringency of state climate change
mitigation programs will be needed to examine this question
more fully.
Conclusion
This examination of states’ adoption of GHG reduction tar-
gets yielded insights into the conditions under which states are
more likely to take action to address climate change. In light of
the polarization of public attitudes and opinions concerning the
causes and consequences of global climate change, we were
particularly interested in the extent to which political ideology
may be affecting state actions.
The results of the logistic regression analysis suggest that the
most important factor in explaining variation in GHG reduction
target adoption is whether the state is located next to a state
whose officials have adopted a similar program. This finding
supports the “horizontal diffusion” of state actions to reduce
GHG’s. Also, those states with relatively low levels of toxic
pollution, and also are in close proximity to another state with
GHG reduction targets, are more likely to implement similar
efforts, providing evidence of a possible “race to the top” in-
fluence at work.
Certainly, the influence of political ideology is confirmed by
the finding that those states with more liberal voters and citi-
zens are much more likely to have set specific targets for reduc-
tions in GHG’s. This suggests that the polarization among the
public concerning climate change may be affecting the choices
made by state officials as to whether to engage in climate
change mitigation efforts.
In future studies it would be useful to examine the specific
GHG reduction targets adopted by the states, especially any
incentives that may be offered to encourage GHG reductions. In
addition, considering whether a state is a member of a regional
climate change alliance like the Regional Greenhouse Gas Ini-
tiative in New England, and the Western Climate Initiative,
may be useful. Also, the inclusion of variables related to fossil
fuel energy production and consumption, as well as alternative
energy production and consumption may be relevant in under-
standing why some states engage in efforts to reduce GHG’s
and others do not. In addition, a look at the degree to which
neighboring states with similar climate policies may also have
similar ideological orientations may yield additional insight
into policy diffusion across states. Finally, close examinations
of leader and laggard states, through case studies, would help to
shed more light on specific contextual factors affecting adop-
tion of climate change policies.
States have an important role to play in devising policies to
address climate change, both in terms of mitigation strategies to
reduce GHG’s entering the Earth’s atmosphere, and in helping
communities to adapt to some of the consequences of a warm-
ing planet, such as planning for extreme weather events. This
analysis provides insight into some of the influences at work as
state policymakers grapple with whether and how to address
climate change, with little direct guidance from the federal go-
vernment. As a result the findings are relevant to theorists and
state policy makers with an interest in climate planning, and for
researchers attempting to estimate future greenhouse gas reduc-
tion scenarios.
REFERENCES
Adger, W. N. (2009). Commentary. Environment and Planning A, 42,
2800-2805. doi:10.1068/a42244
Berry, F., & Berry, W. (1990). State lottery adoptions as policy innova-
tion: An event history analysis. American Political Science Review,
84, 395-415. doi:10.2307/1963526
Berry, W., & Baybeck, B. (2005). Using geographic information sys-
tems to study interstate competition. American Political Science Re-
view, 99, 505-519. doi:10.1017/S0003055405051841
Berry, W., Ringquist, E., Fording, R., & Hanson, R. (1998). Measuring
citizen and government ideology in the American states, 1960-1993.
American Journal of Political Science, 42, 327-348.
doi:10.2307/2991759
Erickson, R., Wright, G., & McIver, J. (1993). Statehouse democracy:
Public opinion and policy in the American states. New York: Cam-
bridge University Press.
Fredriksson, P. G., & Millimet, D. (2002). Strategic interaction and the
determination of environmental policy across US states. Journal of
Urban Economics, 51, 101-122. doi:10.1006/juec.2001.2239
Gray, V. (1973). Innovations in the States: A diffusion study. American
Political Science Review, 67, 1174-1191. doi:10.2307/1956539
Gray, V. (1994). Competition, emulation, and policy innovation. In L.
C. Dodd, & L. C. C. Jillson (Eds.), New perspectives on American
politics (pp. 230-248). Washington DC: Congressional Quarterly
Press.
Gray, V., & Hanson, R. (2008). Politics in the American states: A com-
parative analysis (9th ed.). Washington DC: Congressional Quarterly
Press.
IPCC (2007). Summary for Policymakers. In S. Solomon, D. Qin, M.
42

T. M. CALE, M. A. REAMS
Manning, Z. Chen, M. Marquis, K. B. Averyt, M. Tignor, & H. L.
Miller (eds.), Climate change 2007: The physical science basis. Con-
tribution of working group I to the fourth assessment report of the
intergovernmental panel on climate change. Cambridge and New
York: Cambridge University Press.
Konisky, D. (2007). Regulatory competition and environmental en-
forcement: Is there a race to the bottom? American Journal of Po-
litical Science, 51, 853-872. doi:10.1111/j.1540-5907.2007.00285.x
Lutsey, N., & Sperling, D. (2008). America’s bottom-up climate change
mitigation policy. Energy Policy, 36, 673-685.
doi:10.1016/j.enpol.2007.10.018
McCright, A., & Dunlap, R. (2003). Defeating Kyoto: The conservative
movement’s impact on US climate change, policy. Social Problems,
50, 348-373. doi:10.1525/sp.2003.50.3.348
Moore, M. (2007). Energy & environmental giving in the States. Natio-
nal Institute on Money and State Politics, 1-10. URL (Last checked
23 February 2011) http://www.followthemoney.org
Pew Center on Global Climate Change (2009). President Obama and
climate change. URL (Last checked 26 February 2011).
http://pewclimate.org/obama-administration
Pew Research Center for the People and the Press (2008). A deeper
partisan divide over global warming. URL (Last checked 26 Febru-
ary 2011). http://people-press.org/reports/pdf/417.pdf
Ringquist, E. (1993). Does regulation matter? Evaluating the effects of
state air pollution control programs. Journal of Politics, 55, 1022-
1045. doi:10.2307/2131946
Shipan, C., & Volden, C. (2006). Bottom-up federalism: The diffusion
of antismoking policies from US cities to states. American Journal of
Political Science, 50, 825-843.
doi:10.1111/j.1540-5907.2006.00218.x
Vig, N., & Kraft, M. (2010). Environmental policy: New directions for
the twenty-first century. Washington DC: Congressional Quarterly
Press.
Vogel, D. (1995). Trading up: Consumer and environmental regulation
in a global economy . Cambridge, MA: Harvard University Press.
Volden, C. (2006). States as policy laboratories: Emulating success in
the children’s health insurance program. American Journal of Politi-
cal Science, 50, 294-312. doi:10.1111/j.1540-5907.2006.00185.x
Woods, N. (2006). Interstate competition and environmental regulation:
A test of the race to the bottom thesis. Social Science Quarterly, 86,
792-811.
Wright, G., Erikson, R., & McIver, J. (1987). Public opinion and policy
liberalism in the American states. American Journal of Political Sci-
ence, 31, 980-1001. doi:10.2307/2111232