The report released Sunday by United Nations climate scientists on what it would take to avert the most catastrophic effects of climate change offers little in the way of good news. The old goal of holding the average global temperature increase to 2 degrees Celsius isn’t sufficient — and we weren’t on track to achieving it anyway, because the United States, the worlds second-largest source of greenhouse gas emissions, isn’t committed to it thanks to President Donald Trump’s determination to exit the Paris climate accords. Instead, we need to hold the increase to 1.5 degrees Celsius if we are to have any hope of avoiding mass droughts, famines, refugee crises, destruction of coastal communities and even more frequent extreme weather events. And that doesn’t even speak to the toll on the natural environment, which would see mass extinctions. Put another way, the economic cost of the 1.5-degree rise would be $54 trillion globally, compared to $69 trillion if the average increase hits 2 degrees.
Here’s the bright side, such as it is: We could achieve the lower level of warming with existing technologies. It would merely take a coordinated human response that is unprecedented in scale. Given the political realities, not just here but also in the developing world where climate concerns tend to be framed against the effort to lift massive populations out of poverty, that may sound unimaginable. But if we want to preserve anything like life as we know it, we need to start imagining. Here are a few things a real effort at limiting rising temperatures would mean.
- First and foremost, we would need to radically remake the energy sector. Depending on the mix of solutions we pursue, we would need to cut fossil fuel use for electricity generation in half or more by 2050 (some scenarios say we need to eliminate it almost entirely), and in all circumstances, coal fired power plants would need to all but disappear. Use of renewable energy would need to quadruple and become the dominant form of generation. On the plus side, trends are already headed in that direction, and advances in biomass and storage for energy from solar and wind are encouraging, but we would need to achieve the transformation on a much larger scale than we are now.
- Energy efficiency will be key. Under a status quo scenario, global energy use would rise 75 percent by 2050. We would need to hold that to about 10 percent to achieve the 1.5-degree target, and some groups have modeled scenarios in which the population increases, the economy grows and we still use less total energy in 2050 than we do today. Efficiency is particularly important in industry, which is the second-largest source of greenhouse gas emissions, and in transportation. Better land use, planning and logistics will be needed to cut down on transportation emissions, as well as greater use of buses and trains than cars, trucks and airplanes.
- Meanwhile, we would need to use de-carbonized electricity for more and more of our energy needs, including heating and transportation. The UN report anticipates an increase in the use of low-carbon fuels in the transportation sector from about 10 percent now to 40 percent by 2050. Air travel is a real problem point here — unless the aerospace industry can come up with massive increases in energy efficiency or some as-yet unknown form of non-carbon propulsion, flying would have to become much rarer and train travel much more common.
- Agriculture would change massively. Most scenarios to reduce carbon emissions to the extent necessary rely heavily on bio-energy and carbon capture technology (more on that last part shortly). The bio-energy part of the equation means growing plants for use in generating electricity, whether by burning or some form of chemical energy generation. The plus side is that the plants remove carbon dioxide from the atmosphere while it grows. The down side is that it would displace vast amounts of land that would otherwise be used to grow crops for food needed by an ever-growing population. Likewise, reforestation is an important component of the plans for its ability to pull carbon from the atmosphere and store it long-term, and that, too, squeezes agriculture. A clear consequence of all this is that meat would have to become a much smaller part of the global diet — it is carbon-inefficient to produce, creates potent greenhouse gases of its own (such as methane) and takes up a lot of land.
- Technologies that exist now but which are not deployed on any kind of commercial scale would need to expand massively. Carbon capture is a big one — whatever emissions we produce from generating electricity would need to be captured and stored, likely in geological formations underground or depleted oil and gas fields. It’s technically possible but has not been done in any kind of cost-effective way. The UN panel makes carbon capture, biofuels and other exotic (but existing) technologies a significant part of its plan as a way to apply the brakes to emissions (and even get to net-negative emissions) in the later decades of its forecast, but not everyone is buying that idea. Others have come up with ways to hold climate change to 1.5 degrees Celsius without them (or at least without much of them), but it requires much bigger advances on all other fronts.
- The economic incentives for de-carbonization would need to change. The most obvious way to achieve that is through carbon pricing, whether through a direct tax, or a cap and trade scheme, but the UN panel says the price would need to be far higher than anyone has attempted — $135-$5,500 per ton of carbon dioxide pollution by 2030. To put that in context, Australia had perhaps the most ambitious carbon tax, $23 per ton, enacted in 2013. It worked but was massively unpopular and was repealed a short time later.
All of this sounds daunting, but it’s way harder than that. The problem isn’t that achieving all that would be necessary would necessarily lead us to a poorer future than the present in which we live — the efficiencies and new industries this effort would require are generally expected to be a net positive for the global economy, and the UN found real synergies between its goals for sustainable development in poorer countries and the strategies necessary to combat climate change. But it would require an understanding that grappling with climate will have to be the singular occupation of humanity for decades to come. It may be a lost cause to hope that the current occupant of the White House, he who made no comment on the UN report but has pledged to revive the coal industry, will even begin to recognize the importance of the challenge before us, and that means, at best, two more wasted years.
But we can show our willingness to recognize the urgency of climate change. California has done it with its own carbon pricing plan. Voters in Washington State will get the chance to enact their own. Here in Maryland, we can elect people this fall who will put Maryland on a path toward 100 percent clean energy. There may be no substitute for action by the United States government, but we are not helpless. We know what needs to be done, and we all must start demanding it.
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