Four charts to challenge optimism about drop in US carbon emissions

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In 2009, Energy Secretary Steven Chu best summed up the looming impacts of climate change: “I don’t think the American public has gripped in its gut what could happen.”

Of course, Chu was talking about the problem. But his comments accurately reflect our perception of the solutions as well.

Steady reductions in global warming pollution don’t come from simply sprinkling a few renewables on top of our existing energy system. It’s going to take a pretty dramatic re-thinking of how we design cities, build transportation systems, adapt agricultural operations, and deploy efficiency and clean energy. And that takes an enormous amount of energy and time — far more than the four-year political time cycles we often think within.

However, with the very notion that we need to deploy these solutions now under attack on the national political stage, we’re still far from collectively realizing the scope of that change.

Enter U.S. carbon dioxide emissions. Since 2005, America has seen a nearly 9 percent decline in annual CO2 emissions economy-wide. That’s due to a number of things: Appliances are getting more efficient, vehicles are using less fuel, companies are figuring out better ways to package and ship products, and we’re steadily transitioning our electricity sector from coal to natural gas and renewables.

Oh, the worst financial meltdown and economic crisis since the Great Depression had a pretty big impact too.

Aside from the whole economic crisis, all of these other factors are positive (depending, of course, on the true environmental impact of natural gas) and represent a broader shift toward a cleaner, more efficient economy. But they’re also somewhat worrisome.

First, they represent incremental change. Any change in the right direction is good. But in order to realize rapid de-carbonization, it’s going to take a lot more than a modest increase in the use of insulation and better-performing washing machines. It takes a pretty serious economy-wide undertaking — something that we haven’t quite “gripped in our gut” as Secretary Chu might say.

Second, most of the factors contributing to the decline in CO2 emissions have been enhanced by the economic slowdown. Those efficient washing machines, automobiles, and cleaner energy sources had a bigger impact because people were driving and consuming less.

So what happens when the economy really picks up steam? Are those carbon reductions going to last? A new report out from Climate Central argues no, they won’t necessarily last without some more dramatic changes.

Here are four charts showing why.

1. We are still utterly dependent on fossil fuels.

There’s no doubt about it, we’ve made great strides in deploying energy efficiency and bringing the cost of renewables down. But we have only scratched the surface on the kind of deep cuts in fossil fuel use that we need to see. (That’s part of the reason why scientists say building a pipeline like Keystone XL — a straw into one of the biggest and dirtiest pools of carbon on earth — is such a bad idea). Climate Central’s Eric Larson explains in the report:

The U.S. is the 2nd largest energy user in the world (18 percent of global energy) next to China (21 percent), and more than 80 percent of U.S. energy use is carbon-rich fossil fuel. The country has trillions of dollars invested in infrastructure designed to supply or use fossil fuels: power plants, coal mines, oil and gas wells, refineries, vehicle fleets, houses, office buildings, and manufacturing facilities. Most of this infrastructure is built to be used for decades. Unless such infrastructure is retired earlier than anticipated in favor of lower carbon-emitting infrastructure, fossil fuels are likely to continue to dominate energy use.

We are a petroleum-dependent economy. But we’re at least making our vehicles more efficient, aren’t we? Yes, and those efficiency improvements are important. However, they don’t change the fact that we still love to consume and love to drive. Which brings us to the second chart.

2. We are utterly dependent on cars and still lagging in public transport.

The graph above shows Energy Information Administration projections for vehicle miles traveled through 2050. So even though we’re going to see pretty dramatic improvements in fuel efficiency over the coming decades, we’re also going to see a similarly dramatic rise in driving:

The number of cars on the road in the U.S. has grown steadily for four decades, from about 100 million in 1970 to 250 million in 2010 (ORNL, 2011), and the Energy Information Administration (EIA) projects that the number of new cars purchased in the coming 25 years will follow the long-term historical trend.More importantly from the standpoint of energy use, the EIA projects that the number of miles traveled by light-duty vehicles (cars, vans, SUVs, light trucks) will grow by a trillion miles between now and 2035. The growth in light-duty vehicle population and in vehicle miles traveled could certainly end up being slower than the EIA projects, but dramatic, even unprecedented societal changes would be required to reverse more than 40 years of annual driving increases, particularly in the context of a growing population.

The same goes for our electricity use. Globally, energy use from electronic devices is expected to triple by 2030 — amounting to the combined residential electricity use of the U.S. and Japan combined. And as U.S. consumers buy more gadgets, they will contribute to this trend, adding more to domestic energy consumption. So even with a massive increase in clean energy, we’re adding all kinds of new demands that challenge our ability to scale these resources.

Which brings us to the third chart.

3. Renewables are growing fast, but not fast enough.

Over the last four years, we’ve doubled our share of non-hydro renewable electricity. But let’s say we wanted to add enough renewables to replace our coal generation by 2035 — bringing a 34 percent reduction in CO2 emissions below 2005 levels by 2035. We would need to see a staggering ramp-up in deployment:

Another way to express the numbers is that expansion would be required at an annual average rate more than double the largest single-year addition ever, every year for the next 23 years – perhaps not impossible, but certainly unprecedented. And even if a 34 percent reduction were achieved, it would still fall far short of the 83 percent reduction by 2050 targeted in the Waxman-Markey bill and believed to be needed to help minimize damage from climate change.

As these charts make painfully obvious, we are on a path toward incremental improvement, but nothing close to a road that will bring us to steep emission cuts. And when the economy picks back up, it’s likely that the modest dips in economy-wide carbon emissions in recent years could level off.

So where does this put our options? Behold, chart four.

4. Making strong economy-wide emissions cuts takes serious work.

Climate Central’s Eric Larson provides four scenarios that could help us realize a 38 percent cut in carbon emissions below 2005 levels by 2035 — a target that would put us in line with what scientists say is needed to avoid the worst impacts of climate change.

The various scenarios include:

  • Maintaining driving miles at current levels (unlikely)
  • Strong improvements to building efficiency (very likely)
  • Substantial increases in natural gas (risky)
  • A massive deployment of carbon capture and storage (unproven)
  • An unprecedented increase in renewables (very possible, but a large task).

Combining the likelihood of all these scenarios together, the report concludes:


The recent drop in U.S. carbon emissions is reminiscent of a similar drop that began in 1980 in the wake of the Iranian hostage crisis. That drop in emissions lasted about 4 years: once the shock from skyrocketing oil prices subsided, the country began burning more and more fossil fuels each year. Fundamental forces that drove the increased fossil fuel use that caused the rising CO2 emissions from 1985 to 2005 – a growing population and growing wealth – are forces that will continue to drive increased demand for energy services in the decades ahead. Combined with the enormous dependence of the U.S. energy economy on fossil fuels today, emissions are unlikely to continue to decline once the economy regains steam.

So we’re not there yet.

Of course, we need to continue doing what we’re doing. Any incremental change in economy-wide efficiency is better than nothing. But as this report shows, the recent drop in carbon emissions isn’t a good indicator of our future success.

Unfortunately, it may be too late before we truly grip the enormity of the task in our guts.

 This article was originally published on Climate Progress. Published with permission.
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  • Dave Johnson

    I find it perpetually interesting that estimates of this sort, going decades into the future, almost always appear to have various unspoken assumptions that might be quite important.

    In this case, the forecasters apparently assume that the physical economy will continue to grow more or less as it has historically, despite the obvious fact that various resources, most notably fossil fuels, are getting increasingly scarce and expensive. This not only makes it expensive for individuals to operate vehicles or heat their homes, but also strangles the economic activities, such as manufacturing and transportation, that give people jobs, and thus the incomes, to pay for such things at all.

    Thus, given that the report gives little detail about the underlying statistical analysis, I have to take it with a good-sized grain of salt. And especially so since millions of households and businesses around the world are already starting to switch to alternative energy sources, purely because they are now more cost-effective in a growing number of markets.

    The report also seems to assume that adoption rates for alternatives will be more or less linear, even though it is already clear that they are not. Moreover, recent technological history illustrates that the adoption of useful new technology is not only non-linear, but often very spectacularly so.

    Finally, I’ve been running a personal experiment to see how far I could reduce my carbon footprint while still using the modern conveniences, such as heating, air conditioning, electric lights and computers, that I actually do care about. The result is that my carbon footprint is now down about 90% compared to the average North American, and about half of that can be done with almost no impact on the usual middle-class lifestyle.

    In other words, I have to expect that some combination of dropping incomes and rising costs is going to force people to get a lot smarter about their energy usage, and thus, indirectly, their carbon footprints. The voters may be screaming like spoiled two-year-olds about these trends, and politicians may be doing their best to pander to such emotions, but we are still going to be forced to make some massive changes if we want to continue to live comfortably with the new economic realities.