The New World: Envisioning Life After Climate Change
Not very long ago, scientists warned that this could cause four or five degrees Celsius of warming, giving rise to existential fears about apocalyptic futures. , thanks to a global political awakening, an astonishing decline in the price of clean energy, a rise in global policy ambition and revisions to some basic modeling assumptions. When scientists talk about the path were on today, they are often referring to warming between two and three degrees Celsius, or between 3.6 and 5.4 degrees Fahrenheit a little more than half as much as was projected to be the business as usual future a decade ago. The United Nations confirmed that range in a report released this week. To stabilize the worlds temperatures at the cooler end of that range, two degrees, will require a near-total transformation of all the human systems that gave rise to warming: energy, transportation, agriculture, housing and industry and infrastructure. But, while ambitious and difficult, it now seems possible a very different sort of future, neither a best-case nor a worst-case scenario. Though it would mean environmental upheaval and climatic disruption unprecedented in the long sweep of human history, this is a more hopeful outcome than many dared to believe less than a decade ago. It is also much harsher than many had hoped for. What follows is a partial, hopscotching geography of the jagged new world that climate change is making. As much as our planet has already been transformed by climate change, it will be transformed far more in the decades to come. Everything will move ecosystems, too. At two degrees, according to one study, more than 10,000 plant species would lose half their habitable area. Every place in every part of the world would essentially trade its current climate for a hotter one: One study projected a change for European cities that was the equivalent of moving about 600 miles toward the Equator, or about a dozen miles each year. In the United States, extreme heat will stretch from Texas and Louisiana up through the Midwest, where by the mid-2050s, a report from the First Street Foundation suggests, more than 100 million Americans would be experiencing at least one 125-degree day each summer. According to another report, moving from 1.5 to 2 degrees would mean the number of people experiencing a severe heat wave at least once every five years would roughly triple worldwide. Humans will move, too. The I.P.C.C. estimates that more than three billion people live today in places highly vulnerable to climate change. How many will move? How many will adapt? How many will suffer? The range of estimates is huge, a sign of how much uncertainty about human response hangs over everything we think we know about the climate future. If there is one thing to know about the world at two degrees or even the world today, at 1.2 degrees it is that warming is unjust. The rainfall that led to Pakistans historic monsoon flooding this year was made 50 percent worse by climate change, by one estimate, even though the country has contributed in all its industrial history only as much carbon to the atmosphere as the United States does each and every year. And though the future will be hard everywhere, wealth will enable many places to adapt. In some places, life could even grow more pleasant as the end of fossil fuels also eliminates the millions of premature deaths caused each year by burning them. Cities may turn increasingly away from cars and toward biking and green space. The construction project that lies ahead is vast nearly everything about our built environment will need at least an upgrade and in many cases will have to be totally reimagined. This is a burden but also, for some, an opportunity. One report by McKinsey estimated that, in some scenarios, a transition to net zero emissions could generate more than $12 trillion in annual revenue gains, and not just for solar entrepreneurs. The biggest value pool they identified was transportation; the second biggest, buildings. It is a perverse reality that the nations positioned to manage best, adapting most successfully to their new ecosystems, are likely to be the same nations responsible for most of the worlds carbon output. What about food? At two degrees of warming, yield declines are expected for most staple crops. By one estimate, roughly 40 percent of todays cropland is expected to experience severe drought at least three months a year by 2050. Weather disasters wont just be more intense; they will also be more frequent. Scientists sometimes think about this in terms of return time, the period between catastrophes like hurricanes and heat waves, when devastated communities try to pick up the pieces. At two degrees, what are now once-in-a-decade heat waves would be expected more than five times as frequently, and over a third of the worlds population would be hit with severe heat waves once every five years. The biggest human response will be in power generation. Currently, more than 80 percent of the worlds energy production still comes from fossil fuels. To limit temperature rise to two degrees, it would probably have to fall all the way to zero in the next five decades if not faster. The energy revolution will be even more transformative elsewhere in the world, where hundreds of millions of people today lack access to electricity and could acquire it not by burning coal and oil and gas but through the solar and wind power they already have in abundance. The explosion of this new energy infrastructure will make the new world look radically different from ours. We dont know the exact mix wind and solar are the intuitive choices today, but they may be supplemented or even supplanted by green hydrogen, geothermal or next-generation nuclear. Carbon capture, too the I.P.C.C. has suggested that keeping temperatures to two degrees would require a breakneck, global scale-up of sequestration infrastructure. And then there are batteries, which are likely to be as important to the clean-energy transition as the transistor has been to the computer revolution. Imagine batteries the size of small towns, but also idling electric vehicles used to store power from rooftop solar panels. But less than a decade ago, the world that lay ahead seemed even more disastrous than the one weve just taken a tour of; truly apocalyptic scenarios for all of humanity seemed plausible. Today we are faced with something different: climate upheaval big enough to terrify and intimidate and yet open-ended enough to be wrangled and even managed by politics and human design, as well. Thats because, as we have seen, climate impacts represent only half the story. The other half is human response how we manage those impacts and build a future beyond and around them. We have lost our chance to forestall disaster, and there are reasons to fear the world to come. But it remains ours to make.