The US Climate Change Science Program, which is seeking to produce a comprehensive set of reports on climate change, has been widely criticized as a stalling exercise whose work duplicates that of the Intergovernmental Panel on Climate Change, and whose findings may be prone to political manipulation.

However, the programme yielded some promising outcomes last week, when several participants of a panel it convened published some findings on the apparent discrepancy between the record of warming on the Earth's surface and the change experienced in the troposphere, the lowest level of the atmosphere (see Warming debate highlights poor data).

The climate-change programme had brought together 22 experts to look into the problem. In the course of five meetings and countless e-mail exchanges, the participants conceded flaws in some of the their earlier analyses and produced new data sets, some of which were published online in Science (doi:10.1126./science1114772; doi:10.1126./science1114867; doi:10.1126./science1115640; 2005).

The handling of the lower-atmosphere report over the next few months will help to clarify whether the programme really is a serious attempt to grapple with uncertainty in climate-change science.

The release of the draft report summarizing the panel's conclusions for public review, which was due in June, is being delayed, however. The delay may reflect the intrinsic difficulty of getting a large committee containing disparate views to agree on a final form of wording. But it seems to fit in with a pattern at the climate-change programme, which was criticized by the Government Accountability Office in April for failing to meet a 2004 deadline for issuing a new national climate-change assessment. Critics also point out that since the programme issued a strategic plan just two years ago, some of the completion dates for the 21 reports that it plans to produce have slipped by several years.

US government officials say that they were too ambitious in setting the original deadlines. But they also admit that some of the panels' work is being delayed by two other factors: the need to comply with recent legislation that makes it extremely difficult to incorporate fresh scientific information into government reports, and the requirement that the climate-change work is approved at the political, as well as the scientific, level.

The programme's director, James Mahoney, argues that the latter process will be managed in a way that will preclude political interference. Once the scientific authors have agreed their final draft, the report will be posted online for a 45-day period of public comment. Once that closes, the report will be revised again. Only then, in the final step before publication, will it be reviewed by administration officials.

This process will make it hard for the Bush administration to put its own spin on the report's scientific findings — provided that the drafts are published promptly, without political interference, and that the final documents adhere to the spirit of the drafts. The handling of the lower-atmosphere report — the first from the programme's strategic plan — in the next few months will help clarify whether the programme is a serious attempt to grapple with uncertainty in climate-change science, or is merely an exercise in obfuscation.