Reacting to the most authoritative affirmation to date of the role of human activity in causing global warming, environmentally-oriented students and faculty at Harvard were agreed: Global warming is real, but there is still much that can be done about it.

In its harshest assessment yet of humans’ impact on the environment, the Intergovernmental Panel on Climate Change (IPCC), an international body made up of government representatives and scientific experts, released a summary of its fourth report on Friday, concluding with “very high confidence” that humans have had a significant role in causing climate change and will continue to do so increasingly in the future.

Human activity is causing warmer weather, extreme changes in precipitation patterns, glacial melting, and rising sea levels, according to the report. The panel was able to reach its near-certain consensus due to the increasing availability of documentation of weather patterns and more sophisticated observation tools.

Heinz Professor of Environmental Policy at the John F. Kennedy School of Government John P. Holdren called the report “an affirmation by a prestigious and diverse international body that climate change is real and increasingly dangerous.”

Holdren pointed to the significance of the fact that a large number of scientists from various backgrounds were able to agree with such a high level of certainty.

However, Holdren said, the price of such a consensus is an understatement of the severity of the consequences of global warming due to the wide range of views that were taken into account.

“Most people who are experts would say the IPCC is a conservative floor on what we know,” he said. “The reality is likely to be worse than the middle of the road.”

Addressing the ramifications of the panel’s findings, Holdren said the report should be seen as an urgent reminder of what can still be done to mitigate the effects of climate change. Energy efficiency, cleaner energy sources and reduction of deforestation rates all deserve greater focus in the future, he said.

Citing the numerous climate change bills already in the Senate, and recent appeals from CEOs of major corporations, such as General Electric, calling upon the U.S. to curb greenhouse gas emissions, Holdren said that the U.S. is close to “a political tipping point” regarding the issue of global warming.

“We can still do something about this,” he said, “We cannot stop climate change in its tracks but we do have a choice to take action and avoid the most dangerous consequences.”

Spring Greeney ’09, co-chair of the Environmental Action Committee (EAC), an undergraduate organization devoted to promoting environmental awareness among Harvard students, said the IPCC report has given more power to a student referendum on an initiative titled “A Greener Harvard: Title II,” which took place in December.

The initiative, which passed by an overwhelming 88.3 percent, calls upon the Harvard administration to reduce the University’s greenhouse gas emissions by 11 percent below its 1990 levels by the year 2020.

According to Greeney, a task force of students and administrators is now being assembled to examine the feasibility of such a reduction. The task force is slated to hold its first meeting within the next two weeks. One priority of the EAC, according to Greeney, will be to make the buildings in Harvard’s new Allston campus environmentally efficient.

“Given the action taken so far, especially in light of this report, I think the pressure is on Harvard, and we can step up to the challenge,” she said.