In 1988, against the background of Yellowstone National Park in flames, James Hansen, of NASA's Goddard Space Center, went before Congress to declare that "global warming is at hand."
Last month, Hansen wrote:
The Earth's temperature. . . is now passing through the peak level of the Holocene, a period of relatively stable climate that has existed for more than 10,000 years. Further warming of more than one degree Celsius will make the Earth warmer than it has been in a million years… That implies practically a different planet. ...The Earth's climate is nearing, but has not passed, a tipping point beyond which it will be impossible to avoid climate change with far-ranging undesirable consequences."
But between Hansen's 1988 statement and his most recent one, the Bush Administration has erected a bureaucratic wall between government-funded climate scientists and the press and public. Until the past few years, reporters routinely called scientists at government agencies directly to discuss their findings.
Today, such interviews must be cleared with agency PIO specialists who routinely listen in on the interviews, make notes and, in some cases, terminate conversations.
So Hansen's statements in the lead article of Sunday's New York Times  deserve special appreciation: both for Hansen's candor and refusal to be intimidated but also for some fancy footwork performed by the Times' Andrew Revkin, who essentially shamed NASA's public affairs officials into allowing Hansen to speak candidly and transparently for the record.