Environment & Science

California among 33 states that reduced CO2 while growing its economy

Aerial view of the Diablo Canyon Nuclear Power Plant in San Luis Obispo County, California, on March 17, 2011. The plant will close within the next decade. A new Brookings Institution study questions how California will continue to make ambitious carbon reductions without nuclear power.
Aerial view of the Diablo Canyon Nuclear Power Plant in San Luis Obispo County, California, on March 17, 2011. The plant will close within the next decade. A new Brookings Institution study questions how California will continue to make ambitious carbon reductions without nuclear power.

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A new report from the Brookings Institution's Metropolitan Policy Program has found that 33 states and Washington D.C. have managed to reduce their carbon dioxide emissions while simultaneously growing their economies.

Lead author Devashree Saha said her findings challenge assertions that efforts to fight global warming will necessarily hurt the economy -- a position taken frequently by President-elect Donald Trump during his campaign. 

"Our research completely debunks that notion," Saha said. "The fact that 33 states and DC have managed to de-link economic growth from carbon emissions is a very encouraging trend. Though there is still a very huge gap from where we are and where we need to be. States need to ramp up and do more."

KPCC environment reporter Emily Guerin spoke with Saha about her study. An edited version of their conversation is below.

Interview highlights

Why did you want to do this study?

Saha: In 2014 and 2015, the world managed to reduce its carbon emissions even while it significantly grew its GDP. We also saw national level data that showed that many countries, especially advanced economies in Europe and U.S., had decoupled their economic growth from carbon emissions. We wanted to dig deeper and find out what was happening at the state level.

What did you find?

We found between 2000 and 2014, a total of 33 states and Washington D.C. actually reduced their carbon emissions while at the same time they still managed to grow their economy. At the other end, we had 16 states that haven’t decoupled, instead they have experienced rising emissions along with rising GDP.

You use the word “decoupled” a lot in this study. What do you mean by that?

Decoupled just means any time states have de-linked their economic growth, measured in terms of real GDP, from carbon emissions. Basically your carbon emissions are decreasing and your GDP is increasing.

How important were state policies in helping those 33 states decrease their carbon emissions?

States actually play a huge role in what they can do in terms of reducing their carbon emissions. Think about it: state legislatures actually set and update renewable energy and energy efficiency targets and standards. State public utility commissions regulate investor-owned utilities. States are also the entities that shape land use rules, building codes, and transportation systems. Especially now in a new political reality where the federal government is going to take a back seat on climate and energy, I think the state role is going to be even more critical.

What about market forces? Natural gas prices have been low enough to prompt many power plant operators to make the switch from coal, which is twice as carbon intensive as natural gas.

That’s happening in many parts of the country, and it has been a very important driver in the ability of several states to decouple their emissions from their economic growth.  

Our research surprisingly found that nuclear has been playing a very important role in the ability of states to decouple and decarbonize their economy.  States like Georgia, Tennessee, Virginia, they have all managed double-digit economic growth and double-digit reduction in CO2 emissions. A lot of that has to do with the role played by nuclear in these states. Georgia sources more than a quarter of its electricity from nuclear, Tennessee almost a third.

Meanwhile California is shutting down its last nuclear power plant, Diablo Canyon.  

There is a movement in California towards shutting down nuclear power plants. These are zero-carbon power sources. California has one of the most aggressive emission targets in the country. Basically you’re taking away a zero-carbon power source from your equation. California has to think about how it would achieve aggressive carbon emission targets without nuclear chipping in.

How does California compare to other states in your study?

California is a very interesting example. California is definitely a state that has decoupled but compared to most other states, California’s emissions reduction has been very modest. Between 2000 and 2014, California only was able to reduce its emissions by 6 percent. Compare that to New York, which was able to reduce by 20 percent and Massachusetts by 22 percent.

One of the reasons why the numbers are small for California is California has very little dependence coal to start with. So it kind of deprives California of a leading mechanism for reducing its carbon emissions, which is the fuel switch from coal to natural gas. 

Do you expect the trend you identified in these 33 states to continue under the Trump administration? 

I do feel that many of these states will actually keep the momentum going because they can. There are other states that haven’t decoupled so far. So I don’t know how the situation is going to play out in those states. Whether the election of Trump as president kind of encourages them to keep the status quo, it’s difficult to say.

Do you think your study will change anyone’s mind in the Trump administration? As someone who trades in facts and research, how do you feel right now, a time when facts seem to matter less than ever?

I feel a little depressed (laughs). I mean hey, we are researchers, we deal with facts. We are very proud of that. So I really don’t know whether our research will change the mind of the incoming administration, but I do feel that our research will resonate with a lot of state-level policymakers and other policymakers at the subnational level. And in a way, probably that’s where the action is, so that’s good.