A Statue of Liberty replica by Danish artist Jens Galschiot at the “Climate March” demonstration in Bonn, Germany, on Saturday. The 2017 U.N. Climate Change Conference COP23 will take place from Nov. 6 to 17 in Bonn. [Photo by OMER MESSINGER/EPA-EFE/REX/Shutterstock (9188948bu)]

COP 23, which marks the 23rd annual international climate change negotiations, begins Monday in Bonn, Germany. The primary objective of the meeting is to finalize the rules to implement the 2015 Paris Agreement.

But the politics over the next two weeks will be just as important, given President Trump’s announcement in June that the United States would withdraw from the Paris Agreement. The U.S. government continues to give mixed messages on climate change and lacks a clear policy.

On Friday, a comprehensive U.S. government-issued scientific report on climate change confirmed the global consensus that climate change is the result of human activity — a connection that the Trump administration has denied.  But on Thursday, the White House confirmed that it is organizing an event in Bonn that will emphasize the role of  fossil fuels and nuclear technology in helping developing nations meet their energy needs, a position sharply at odds with the goals of the Paris Agreement.

Here’s a rundown of what to expect on the policy and politics of the Bonn meeting.

The policy issues: How countries will implement the Paris Agreement

The world celebrated the signature of the landmark Paris Agreement in December 2015. Each of the 195 signatories pledged to take action on climate change, deciding on its own policies and approaches to meet these goals — the “choose your own adventure approach” to climate policy.  Known as  “Nationally Determined Contributions” these pledges are the foundation of the Paris Agreement.

Since then, countries have been working steadily on the Paris Agreement implementation plan. Following last year’s meeting in Marrakech, Morocco, countries are finalizing the rule book — the rules and procedures to implement the Paris Agreement.

Of the myriad topics covered in the rule book, transparency and review are the most important. In order for the “choose your own adventure” approach to work, countries have to produce reliable data and implement a process for reviewing their commitments. The rule book thus needs robust procedures for measuring and reporting each country’s efforts.

The other key policy discussion will be to tee up a “facilitative dialogue” scheduled to take place in 2018. To achieve the ambitious goal of limiting warming to “well below” 2 degrees Celsius, countries will have to increase their efforts to reduce emissions rather quickly. The Paris Agreement creates a “ratchet mechanism” to review countries’ commitments regularly and increase their ambition.

Although the details are only beginning to take shape, the general idea is clear: The facilitative dialogue will be a preliminary assessment of how states are progressing toward the 2-degree target. So, expect the Bonn negotiations to produce a consensus on the structure of this first critical step.

The political issues — China leads while the United States waffles

 Trump’s announcement of the U.S. withdrawal from the Paris Agreement prompted strong rebuke from many nations. But there’s a legal catch: Withdrawal will take four years and, thus, could be reversed before taking effect.  Nonetheless, Trump’s stated opposition provides an opportunity for leadership from elsewhere — notably, China and the growing number of state and local governments that committed to action on climate change.

China is clearly stepping into the leadership void.  At the recent Communist Party Congress, President Xi Jinping declared that China “had taken a driving seat in international cooperation to respond to climate change.” China’s aggressive investments in renewables and its falling carbon intensity are strong evidence that this is more than empty rhetoric. Beijing also stepped up pressure on the United States to recommit to the Paris Agreement, sending clear signals of its intentions to play a leadership role in Bonn.

China’s firm commitment and leadership role stand in stark contrast to the U.S. waffling on the Paris Agreement. In addition to the mixed messages last week, a leaked diplomatic cable from Secretary of State Rex Tillerson in August suggested there is no clear U.S. policy on climate.  Trump has noted that the United States might consider re-entry on “better terms.” But since the United States created its own commitment on reducing emissions, it’s unclear what those “better terms” would look like.

Without any specific and clear instructions, and mixed signals from different parts of the government, lead negotiator Thomas Shannon, a career diplomat appointed by President Barack Obama, may have some leeway to contribute constructively to the Bonn discussions.

But there’s a second political arena to watch. Bonn will showcase the continued and growing role for sub-state and non-state actors in the climate regime: business, NGOs and sub-national and local governments. Trump’s intended withdrawal prompted the creation of the “We Are Still In” campaign: Thousands of U.S. state and local governments, businesses, investors and tribes have pledged to continue to take action on climate change.

California continues to lead the charge. Gov. Jerry Brown (D) recently announced the 2018 San Francisco Global Climate Action Summit, which will convene a diverse set of actors from around the world to push the Paris agenda forward. Together, these actors will play a significant role in the implementation of the Paris Agreement.

And expect to hear much more on the importance of adaptation and resilience policy. In the wake of the devastation wrought by Hurricanes Harvey, Irma and Maria, there will likely be more talk about the vulnerability of islands and low-lying cities. Fiji — a small island state — is chairing the Bonn negotiations, and has emphasized the importance of better policies to promote resilience to storms and floods, among other climate change impacts.

This is an important U.S. conversation as well. The Government Accountability Office just reported that climate change already is costing the U.S. government tens of billions of dollars a year. This discussion will sharpen as thousands of Puerto Ricans leave their island, and the United States deals with the costs of rebuilding after the recent storms.

There’s a lot at stake in Bonn. China is poised to take its place as a great power in geopolitics, by throwing its weight behind international cooperation on climate change. Businesses, NGOs and state governments will continue to show that climate policy is not just the stuff of international meetings. And we will all be reminded of the hot, hard truth: Climate change is here, whether we choose to act or not.

Jessica F. Green (@greenprofgreen) is assistant professor of environmental studies at New York University. She is the author of “Rethinking Private Authority”, published by Princeton University Press.