There is plenty of both bad and good news in the landmark science report the Intergovernmental Panel on Climate Change released October 8 from Incheon, South Korea. The bad news is that a 2 degree Celsius global temperature rise—long regarded as a relatively safe guardrail against apocalyptic disruption of the climate system—is now officially recognized as being catastrophically dangerous. The IPCC’s special report “Global Warming of 1.5<° C” warns that even 2 degrees C will bring a staggering increase in the heat waves, droughts, storms, and sea-level rise that are already battering people, places, and economies the world over, and will expose hundreds of millions of people to higher risks of displacement, water shortages, and poverty. The good news is that humanity can still avoid this fate. In a further revision of climate orthodoxy, the IPCC report declares that limiting global warming to 1.5 C is possible, though it will require revolutionary changes in government and investment policies for which “there is no documented historical precedent.”

“One point five degrees is the new 2 degrees,” said Christopher Weber, the global climate and energy lead scientist at the World Wildlife Fund. But it will be far from easy to hit a 1.5 C target; the experts who’ve said that it’s impossible are not all fools and knaves. The next 12 years will be decisive: By 2030, carbon emissions worldwide must fall by a massive 45 percent (from 2010 levels). And they must continue that steep decline and achieve net zero emissions by mid-century. The world as a whole remains far from this trajectory, but the fact that California, the fifth-biggest economy on earth, is officially committed to just such a path—and is prospering economically along the way—indicates that other jurisdictions could do likewise.

Implicit but unmentioned in the IPCC report, and in most news coverage of it, is that holding the 1.5 C line will require not only a deep technological revolution but also a justice-led social transformation. The report makes clear that burning coal must “decline very substantially” by 2050, while oil and natural-gas burning must also sharply fall. If that is to happen, workers and communities whose livelihoods currently rely on fossil fuels will need help transitioning to a clean-energy future. Since this transition must be global, less-developed countries will need financial and technical assistance to shun fossil fuels, deforestation, and other climate-destabilizing activities, not to mention to protect themselves against the harsher heat waves, droughts, storms and sea-level rise that even 1.5 C will deliver.

One can be forgiven these days for thinking that such a justice-led transformation isn’t on the agenda. Nevertheless, we had damn well better try to deliver it; in fact, it’s our only hope. The opportunity, and the imperative, here is to leverage the green-tech revolution and the climate-justice vision to maximum advantage. We are in a deep hole, and it’s going to take both legs to climb out of it.

Indeed, the hole may be deeper than the IPCC indicates, for this special report did not directly address the question of “runaway” global warming. But a separate blockbuster scientific report released in August, the Hothouse Earth study, warned that even 2 C of global temperature rise could well cross “tipping points,” such as triggering the die-back of tropical forests or the release of methane-rich permafrost, that would release still more heat-trapping gases and thus drive temperatures to beyond what civilization could survive. In other words, even a 2 C future could yield a situation where, no matter what humanity belatedly does to cut emissions, our efforts will be swamped by runaway feedbacks.

Nor is the risk of runaway warming the only salient issue excluded from the IPCC report. Its all-important “Summary For Policymakers,” the only part of the report most people read, was subjected to intense negotiation in advance of publication, with the governments of the United States and Saudi Arabia reportedly demanding significant softening of language. At least two justice-related statements were cut from the summary: one endorsing “[financial] transfers to secure the equity of the transition,” and another forecasting that 2 C could unleash “significant population displacement, concentrated in the tropics.” Citing such omissions, Bob Ward, the policy and communications director of the Grantham Research Institute on Climate Change and the Environment, told The Guardian that the new IPCC report was in fact “incredibly conservative.”

The big, and very welcome, surprise in the IPCC report is that a 1.5 C future is technically achievable. When the world’s governments agreed at the 2015 Paris climate summit to limit global temperature rise to “well below 2 degrees C above pre-industrial levels,” while “pursuing efforts to limit the temperature increase to 1.5 C,” the 1.5 C reference was widely seen more as a political concession to poor and vulnerable countries than as a realistic policy goal. Now, in 2018, the IPCC has definitively declared that 2 C in fact invites disaster. That would be dire news indeed except for the panel’s finding that a 1.5 C future is still within reach—a finding that surprised some of the IPCC experts. “Two years ago, even I didn’t believe 1.5 C was possible,” Jiang Kejun, a scientist at China’s Energy Research Institute and a co-author of the IPCC report, said at the press conference where the report was released. “But when I look at the options, I have confidence it can be done.”

All nuance aside, achieving a 1.5 C future will require reaching global net-zero greenhouse-gas emissions by 2050, the IPCC says, and this can be done. Although the report says that this will require changes “of unprecedented scale” in energy, transport, land use, and other systems, that is not entirely accurate. Jim Skea, a co-chair of the IPCC panel and professor at Imperial College of London, told the press conference that solar, wind, and other forms of renewably generated electricity have made remarkable progress in recent years—progress, Skea added, that must now be replicated in other economic sectors. Reducing emissions alone will not suffice; humanity must also extract a significant amount of the carbon that has already been emitted into the atmosphere. “There is no pathway to 1.5 C that does not include some form of carbon removal,” said Skea.

The IPCC report joins other studies in urging that the technological breakthroughs that have recently disrupted the electricity sector be extended throughout the global economy. “The Exponential Climate Action Roadmap” released at the Global Climate Action Summit in San Francisco last month details scores of feasible technology and policy shifts that could deliver a 1.5 C future by cutting emissions by half every decade, starting now. Many of the shifts are described in Project Drawdown, including such wonky but far-reaching reforms as replacing inefficient refrigeration. At the press conference, Skea referenced another big innovation: moving the transport sector off of gasoline by fueling cars and trucks with zero-carbon electricity instead, which happens to be a core element of California’s climate policy.

Yet, given how challenging it will be to cut emissions by half every decade between now and 2050, technology alone will not be enough. The 1.5 C carbon budget is much smaller than the 2 C budget; at current emissions levels it will be exhausted in about 12 years. If you’re a developing country, still unsure that there’s a way forward without fossil energy, this does not sound good. The global climate transition cannot succeed unless it “opens doors for sustainable development and for lifting many people out of poverty,” insists Gebru Jember Endalew, the head of the Least Developed Countries negotiating group. The IPCC scientists agree, emphasizing that the reforms needed for a 1.5 C future can be compatible with the UN’s Sustainable Development Goals of reducing poverty and increasing health and education worldwide. Indeed, the closing pages of the policymaker summary are thick with talk of sustainable development, poverty alleviation, and the need to reduce inequality. There are even kind words for “redistributive policies across sectors and populations that shield the poor and vulnerable,” which is probably why Trump administration negotiators repeatedly complained that the text had an “outsized focus” on sustainable development.

We’re also going to have to deal with the problem of wealth, which includes the problem of overconsumption. The IPCC report addresses this in a particularly useful way, describing a “Low Energy Demand” emissions pathway that focuses less on technological breakthroughs and more on the universal global attainment of a “decent living standard.” The details are many, but the point is simple. A push for using energy and natural resources much more efficiently, combined with a radical narrowing of economic inequality, can meet “the 1.5 C climate target as well as many sustainable development goals, without relying on negative emissions technologies.”

The next big issue in climate negotiations, which are set to resume in December in Poland, is strengthening the national pledges of action, which currently are far too weak to hold the 1.5 C line. Progress will be challenging, given the poisons that the Trump administration has injected into the talks, including Trump’s plan to withdraw the US from the Paris Agreement. Trump also blocked a $2 billion contribution president Barack Obama pledged to the Green Climate Fund, which is charged with facilitating poor countries’ shift to climate-friendly technologies and practices. It will be extremely difficult to strengthen national pledges while the message from Washington is that developing countries are on their own.

And if we don’t heed the scientists’ warning? Mainstream news coverage has ably highlighted the IPCC report’s list of projected impacts if the earth warms by 2 C rather than by 1.5 C. Hundreds of millions of people would be more likely to endure poverty. Heat waves would get much worse. The record heat wave that struck Europe in 2003, killing over 71,000 people, was a one-in-100-years event at the time. Such extreme heat waves would be 50 percent more common in a 2 C world than a 1.5 C world. At the poles, the difference between 1.5 C and 2 C will be particularly severe. Think ice-sheet instability, which directly threatens sea-level increase. A 2 C future would expose at least 10 million more people living along coastlines to inundation. “Every fraction of a degree of warming we can avoid matters,” says Peter Frumhoff of the Union of Concerned Scientists. “Human lives can be saved, and coral reefs, wetlands, and other vulnerable species and ecosystems better protected. The risk that the Greenland and Antarctic ice sheets will ultimately melt, leading to catastrophic sea level rise, will also be lower.”

The climate transition is going to be as hard as anything human beings have ever done. It raises immense justice challenges, challenges that require the same kind of concentrated attention that has, to this point, been focused on the ins and outs of science and technology. The IPCC report is a milestone in this long overdue reorientation of the climate debate. Ultimately, however, it’s not going to be the IPCC that answers the fundamental questions facing us, for those questions are not scientific questions. They are questions of morality, justice, and the political and economic actions needed to achieve them, and they involve all of us.