The climate is warming, it’s warming because of human activity, and it’s time to do something about it.

These are the conclusions of America’s Climate Choices, a series of studies released Wednesday by the National Academy of Sciences National Research Council. Three reports in the series—Advancing the Science of Climate Change, Limiting the Magnitude of Climate Change, and Adapting to the Impacts of Climate Change—were released at news conference and Webcast featuring interviews with lead authors. Two more documents will be released later this year.

“The state of climate change science is strong, and the scientific community needs to continue to expand on its understanding, and focus on when and where the most severe impact will occur,” NAS President Ralph Cicerone said.

The first report, Advancing the Science of Climate Change, isn’t likely to surprise most people who’ve followed the issue. Stanford University’s Pamela Matson, who shepherded the report, said the work emphasizes clear conclusions about what we’ve learned so far.

These include that the earth is warming—the past decade is 1.5 degrees Fahrenheit warmer on average than a decade one hundred years ago—surface and ocean temperatures are increasing, the sea level is rising, and ecosystems are being affected. Concentrations of greenhouse gases are increasing and “there are clear fingerprints that link them to human activities,” she said. The laws of physics—in the incarnation of the enhanced greenhouse effect—assure that warming will continue into the future.

From a hazards perspective, the consequences of a warming globe are also unsurprising. We can expect more and more severe heat waves, stronger ocean storms, heavier rainfalls, and alterations of traditional hydrology. The curveball, as the two subsequent reports make clear, is where these events occur. That will depend on regional climate factors, an area of research and knowledge that is less certain.

Keeping with the same old story theme, the contentious issue of how we address these problems hasn’t gotten any less ambiguous either. Robert Fri of Resources for the Future said that while his group—which produced Limiting the Magnitude of Climate Change—didn’t identify a specific target for U.S. carbon emissions, other research suggests the nation needs to limit emissions to less than 170-200 billion tons between 2012 and 2050 if warming is to be curbed. At current rates, this “budget” would be exceeded well before 2050. Furthermore, the technology needed to meet this carbon emissions budget isn’t available.

“Even if all available and emerging technology—efficiencies, renewable, nuclear, carbon capture and storage for coal plants and biofuels—even if all those can be deployed to their fullest technical potential, it’s clear that we will still need new and additional emission reduction options if we’re going to meet that budget,” Fri said. “And so, a principal conclusion of our report is that the country needs both a prompt and a sustained national commitment to reducing greenhouse gas emissions.” The national commitment should also include “potential equity implications…with special attention to disadvantaged populations,” he said.

Limiting the Magnitude of Climate Change calls for a carbon pricing system, although it does not address whether to use cap-and-trade, carbon taxes, a combination, or some other scheme. The financial incentive would be used to drive new technologies in both government and private sector initiatives.

The third report, Adapting to the Impacts of Climate Change, tackles the decision processes needed to address climate change impacts. Because climate change will impact the Gulf Coast differently than the Northwest and the Rockies differently than California, local and regional actions must set the pace.

“Adaptation to reduce vulnerabilities associated with likely impacts of climate change cannot be accomplished by the federal government or any other single decision maker alone,” the report states. “The challenges are too diverse, the contexts are too different, and too many parties have knowledge and capacities to contribute.… Adaptation planning and action will be required across all levels of government as well as within the private sector, non-governmental organizations, and community organizations.”

Despite the time and expertise that went into the long-awaited reports, even their recommendations are subject to uncertainty. Even in the best-studied arena, no one can predict regional impacts with much confidence or say if the climate system has a “tipping point” at which abrupt change occurs. As one questioner at the press conference pointed out, it’s unclear if we would recognize abrupt climate change if it were to occur. The summer Arctic may be ice-free within a decade. Is that abrupt climate change? And whether it is or not, what are consequences? No one knows.

Two additional reports in this series will be released later this year. Informing Effective Decisions and Actions Related to Climate Change will examine how to best provide decision makers with information on climate change. A final summary report, America's Climate Choices, will offer a scientific framework for the policy decisions underlying the nation's efforts to confront climate change.