An influential group of scientists led by James Hansen, the former NASA scientist often credited with having drawn the first major attention to climate change in 1988 congressional testimony, has published a dire climate study that suggests the impact of global warming will be quicker and more catastrophic than generally envisioned.

The research invokes collapsing ice sheets, violent megastorms and even the hurling of boulders by giant waves in its quest to suggest that even 2 degrees Celsius of global warming above pre-industrial levels would be far too much. Hansen has called it the most important work he has ever done.

The sweeping paper, 52 pages in length and with 19 authors, draws on evidence from ancient climate change or “paleo-climatology,” as well as climate experiments using computer models and some modern observations. Calling it a “paper” really isn’t quite right — it’s actually a synthesis of a wide range of old, and new, evidence.

“I think almost everybody who’s really familiar with both paleo and modern is now very concerned that we are approaching, if we have not passed, the points at which we have locked in really big changes for young people and future generations,” Hansen said in an interview.

The research, appearing Tuesday in the open-access journal Atmospheric Chemistry and Physics, has had a long and controversial path to life, having first appeared as a “discussion paper” in the same journal, subject to live, online peer review — a novel but increasingly influential form of scientific publishing. Hansen first told the news media about the research last summer, before this process was completed, leading to criticism from some journalists and fellow scientists that he might be jumping the gun.