Los Angeles is not one of those gracious cities that are kind to visitors. Its urban surprises, rather than expanding one’s horizons, often involve unpleasantness. Last summer I had a visitor from New York. A few days into his stay the mercury hit 95 degrees, and he had the understandable impulse to visit the Santa Monica beach. We fought heavy traffic all the way there. What should have taken 15 minutes took more than an hour. We tried to entertain each other with conversation. He’s a committed environmentalist, and the traffic was a perfect excuse to talk about L.A.’s famous orientation toward the automobile. Surveying the 10-lane freeway, he said, “Seeing L.A. reminds me how difficult it is to stop burning fossil fuels. How do you change habits and even begin to address climate change when so many lives have been built around the car?” It was a tough question, and as we sat silently contemplating it, I knew his opinion of the city was sinking. He gazed at the idling cars emitting tons of heat-trapping carbon dioxide. I made a lame attempt to emphasize the positive. “Did you know that in 2008, L.A. County voters passed a ballot measure raising the sales tax to pay for public transit projects? Right now they’re using the funds to build a light-rail line from downtown to Santa Monica.” “Really?” he replied. “When’s it going to be done?” There was a moment of silence. “I think 2016,” was my feeble answer. I knew it was a setup for his snarky response: “Really? How many years before you even have the option of a low-carbon trip to the beach? At that rate, we might as well just build seawalls and forget about climate change.” I laughed politely.
My houseguest had a point. Even if the entire world were to imitate California and Europe, it would still require a long time to slow increases in greenhouse-gas emissions, let alone reverse them. Renewable energy could become cheap enough to be competitive with fossil fuels without market intervention. But even if there were breakthroughs tomorrow, they would still take years to evolve from concept to marketable products. The most rapid shift possible from fossil fuels to renewables would probably take at least a decade or two. So we’ll be emitting greenhouse gases for some time no matter what choices we make now about energy. Couple that with the fact we’re already committed to some change from our previous greenhouse-gas increases, and it seems clear: Significant climate change is impossible to avoid.
When we finally arrived at the beach, my friend tore off his shoes and raced to the water. He got out far enough to submerge his calves before running back, yelling, “That water is freezing. It’s so hot out. Why is the water so cold?” In front of most people, those words would have been a rhetorical shake of a fist at the sky. But as he realized he had uttered them in front of a climate scientist, I could see the weary amusement sweep across his face. “Oh no, you’re actually going to answer that question.” “Of course,” I said, smiling. “When the sunshine hitting the northern hemisphere undergoes its annual increase from winter to summer, the temperature of the ocean increases a lot more slowly than the land. This is because so much more heat is needed to raise the ocean temperature one degree. So the temperature of the ocean ends up peaking at a lower value than the land. That’s the most important reason you’re so shocked about the water temperature. But ocean currents also make this patch of the Pacific especially cold.” He tilted his head down and looked up at me. “Okay, well now we know why this beach isn’t as fun as it could be.” This time I laughed for real.
The relatively slow ocean warming in response to increasing sunshine does more than disappoint beachgoers. It has an exact parallel in climate change, creating a lag in warming. In computer-based simulations of the climate system’s response to increasing greenhouse-gas concentrations, the ocean receives the same amount of extra heat from the greenhouse-gas buildup as the land does. But it registers a much slower warming. Likewise, as greenhouse-gas concentrations have increased over the past century, the accompanying temperature increase has generally been smaller over oceans than over continents. This effect works to our advantage because it gives us more time to adapt to a changing climate—especially in coastal areas, where climate is influenced by the ocean. But it’s also symptomatic of the irreversibility of climate change. The ocean eventually has to adjust fully to enhanced heat input. So the global warming we see at any given time doesn’t fully reflect what will ultimately materialize as a result of the previous greenhouse-gas buildup. This leads to a disconnect between the current state of the climate—which probably has the greatest influence on our perceptions of climate change—and the eventual climate change we are already committed to, thanks to our past burning of fossil fuels.
There’s momentum behind climate change for another reason, but this one is related to the inertia of human habits rather than to physics. It’s impractical for us to stop burning fossil fuels right away, even if we collectively decided to. California, much of Europe and other localities are creating incentives to transition away from fossil fuels. In these jurisdictions, efforts are under way to lower carbon footprints. The light-rail line to Santa Monica is an example. But as I noted to my skeptical houseguest, even though Angelenos have largely embraced new rail transportation projects, this line won’t be finished until 2016. And it’s one of the first elements of a regional rail network that will take decades to complete.
Most people seem to grasp the inevitability of climate change. Ask a climate scientist what question he or she usually gets at cocktail parties, and it’s something along the lines of “Based on your research, are we totally screwed?” It may also be the underlying reason why some people deny climate change: The problem may seem too insurmountable to grapple with. For sanity’s sake, we might as well change the subject to something we can grapple with.
The inevitability of climate change was underscored for me when my UCLA research team and I completed a study on what climate change will mean for Los Angeles in the middle of this century. Our research shows that if greenhouse-gas emissions are curtailed over the coming decades, the most likely warming in the region will still be 70 percent of what would occur if greenhouse-gas emissions continue to increase. Climate scientists work with standardized scenarios of greenhouse-gas emissions to predict future climates. We worked with a scenario of reduced emissions we nicknamed “mitigation” and a scenario of rising emissions we called “business as usual.” Both scenarios result in significant regional warming: about 2.9 degrees Fahrenheit under the mitigation scenario and 4.2 degrees under business as usual.
Put differently, immediate and far-reaching global measures to reduce our carbon footprint over the coming decades would reduce midcentury warming in Los Angeles by only 30 percent. When we examined other aspects of climate change in the region—such as changes in snow, water resources, winds and wildfire—we reached the same conclusion: Reducing greenhouse-gas emissions attenuates climate change somewhat, but it doesn’t lead to dramatically different outcomes. A similar story can be told in other regions or for the entire planet. According to a recent report of the Intergovernmental Panel on Climate Change Fifth Assessment, the most likely midcentury rise in global sea level will be nine inches under the mitigation scenario and 10 inches under business as usual.
We have no choice but to think seriously about how to adapt to changing climatic conditions, no matter what we choose to do about emissions.
Given this conclusion, it may seem wise to simply adapt to climate change and be done with the whole issue, as my houseguest sarcastically suggested. We’re also not good at the long-term planning required to reduce greenhouse-gas emissions. This deficiency is especially apparent in the way we make economic decisions: Most people don’t plan adequately for retirement. A perennial complaint about corporations is their tendency to focus on quarterly earnings instead of long-term profitability. Governments borrow money to enact popular tax breaks or to spend, without giving thought to affordability in years to come.
When it comes to reducing greenhouse-gas emissions, the inability of governments to make long-term plans is perhaps the most crucial obstacle. Elections come every few years in Western democracies, where much of humanity’s emissions occur. Any politician who implements long-term reform will pay a price at the ballot box as soon as the reform begins to cause economic pain. And that politician won’t be around to see any political benefit when the reform bears fruit. Meanwhile, the state-capitalist regimes of East Asia, the planet’s other big carbon emitters, rely on consistent economic growth to perpetuate their authority. They don’t make structural economic changes easily either. With short-term thinking dominating politics in countries with the highest emissions, meaningful regulatory efforts to reduce greenhouse-gas emissions—such as a cap-and-trade system or a carbon tax—are rare.