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I’m a climate scientist headed to Paris next week for the 21st round of U.N. Conference of Parties climate talks because I believe this time will be different. Why? Science.

In less than one week, will establish an international agreement on the reduction of carbon dioxide, methane, and other greenhouse gas emissions required to keep global warming below 2 degrees Celsius. But individually and collectively the commitments countries have made in advance of COP21, even if carried out to the letter, , allowing warming to 2.7–3 degrees. I’m making the trip to observe the talks and join in with organizations demanding better commitments than that.

Let’s examine the evidence: Has science sufficiently warned the planet so that we can take action? Has the scientific community provoked policy change? Has science inspired and supported movements for climate and social change?

Yes, yes, and yes.

Scientists have been publishing the dire consequences of global warming since the 1970s, when Yale professor William Nordhaus predicted that sea level rise and “hardship in low-lying areas” would accompany 1 C of global temperature warming, a level we recently achieved, .

And what about me, just one scientist? I study the effects of the . I see that ice is melting sooner, forming later. Spring algae blooms in the Arctic are occurring earlier, lasting longer. I spend weeks on the ice doing field work near indigenous communities that are among the first to suffer from climate-based changes to their food sources, directly aggravating their struggle with poverty and food security. I write papers, create posters, and speak in classrooms about what I do and what I have learned. I am aware that all of my colleagues are also spending each day like this, confronting Earth’s changes every hour of their working lives. I think we are learning to do a better job telling the story of what has happened and will happen to the planet, and why.

But that’s not enough.

From science to radical change

As fascinating as it is to study, I don’t want to see climate change. The change I do want to see is nations responding to the widespread calls for limiting carbon emissions from fossil fuels. We can make better choices about agriculture and forest land use, and governments need to assure safe and healthy lives for their citizens. Personal and social transformation go hand-in-hand. One person alone changes very little, but unjust authority can be overturned when many people work together with passion and discipline. I’m driven to discover the path from science to policy to radical change. How does this happen?

One of the most influential papers in the history of climate science was published six years ago, and it was only six pages long. “” changed the way scientists and activists alike advocated for climate change policy by shifting the conversation from concentration to accumulation. Malte Meinshausen and colleagues created a carbon budget, showing that we can emit only 565 more gigatonnes of carbon into the atmosphere before 2050 if we want to reliably limit warming to 2 degrees. Further, they found that at current rates of carbon emission, we will blow this 565 gigatonnes budget by 2024. This immediately transformed the science and policy questions to how much coal, oil, and natural gas is and how can we quickly slow down our burn rate?

By 2012, Bill McKibben and 350.org had seized on this idea of the carbon budget with their brilliant “Do the Math” tour and movie, that activists could use:

1. We need to keep global warming below 2 C.

2. To do that we can only emit roughly 565 more gigatonnes of carbon into the atmosphere.

3. The scariest of all, the amount of fossil fuel recoverable under current economic conditions is five times that, or 2,795 gigatonnes.

The result? The climate movement is successfully promoting a “leave it in the ground” fossil fuel strategy, divestment in the financially risky fossil fuel sector—whose net worth may plummet by 80 percent because of those “stranded assets”—and instigating to investigate ExxonMobil and other fossil fuel companies for organizing a sustained deception campaign disputing climate science and failing to disclose truthful information to investors and the public.

These campaigns have led hundreds of thousands of people into the streets to demand specific limits on carbon emissions and helped to topple the Keystone XL pipeline. After the People’s Climate March in New York City, in September 2014, , “Our citizens keep marching. We cannot pretend we do not hear them. We have to answer the call.”

For the climate movement, science provided the numbers, and the numbers added up.

Scientists as activists

Using this carbon budget, science has identified the radical changes needed in how we produce and distribute electricity, in the forms and modes of transportation we use, in the use and care of agricultural and forest land, and in how much energy we must conserve in our homes, buildings, and industries. Unlike at previous climate talks, countries are coming to the table with science-backed contributions that challenge the business-as-usual approach.

Yes, some rich countries will try to buy their way out. Switzerland, for example, proposes  rather than making actual reductions itself. Yes, the U.S. moved the goal post by basing their 35 percent reduction on 2005 levels. U.S. carbon emission commitments to 2030 actually represent a 15 percent increase from the internationally recognized benchmark date of 1990.

Yes, some of the reductions we are sold are a lie. For example, greenhouse gas emissions due to movement from coal to fracked natural gas fuels appear lower until you factor in methane leakage from gas drilling sites, pipelines, and flaring. Until such “fugitive emissions” are resolved, the greenhouse gas footprint of fracked gas is larger than coal, and gas plays no transitional role toward real reductions in climate warming.

But science is getting in the way of business-as-usual. COP21 representatives will return home to popular movements increasingly demanding radical change. Outside the formal COP21 talks, popular movements will take advantage of this unique moment in history to engage in about how the climate movement and other social movements can unite around common goals. When we consider, for example, the inattention to the physical, environmental, and cultural destruction of the Arctic communities shared by polar bears, whales, walruses, and Inuit alike, the questions and urgency for action are very similar to those raised by Black Lives Matter and Idle No More when discussing human rights.

Popular movements need to take note that science has demonstrated the links between . Similarly, we must link climate, refugee support, and antiwar movements. Green and anti-austerity parties are proposing climate stabilization strategies focused on clean renewable and efficiency investments, demanding large-scale public investment. We, the people, will also win by proposing specific carbon budget objectives.

Scientists have and will continue to get uncomfortably in the way of things, creating a new narrative for change.

For example, climatologist Michael E. Mann, whose 1999 “hockey stick graph” of the mean temperature record of the past 100 years demonstrates the uncharacteristic and rapid nature of current warming, helped establish , where claims of climate deniers are soundly and scientifically debunked.

Intergovernmental Panel on Climate Change lead author Petra Tschakert has called to task U.N. Framework Convention on Climate Change executives on their apparent acceptance of carbon emission targets that lead to a 2 C warmer world, calling the resulting “danger, risk and harm … utterly unacceptable.” Her passionate argument is not just about a specific temperature target. Rather she sees at stake “a commitment to protect the most vulnerable and at-risk populations and ecosystems.” Agreeing, former NASA climatologist James Hansen has called the 2 C target “highly dangerous,” backing it up with .

Scientists are “people like you, with hopes and dreams and loved ones,” stories from MoreThanScientists.org remind us. “We are mothers, fathers, farmers, fishermen, hikers, hunters … and we’re concerned.”

The world depends on continued conversation with scientists. So I’m headed to Paris in a few days to raise my voice.