The first major independent review of criticisms of the global assessment of climate change led by the United Nations declared today that it found "no errors that would undermine the main conclusions" of the panel of international scientists that climate change will have serious consequences around the world.

However the Dutch panel of experts claims it found 12 errors - from a criticism of the number of people in Africa at risk of water shortages to mistakes in references or typing. It also suggested the summary version of the report had portrayed an over-dramatic picture by putting the emphasis on negative impacts of climate change, and it failed to explain some of the threats were not only driven by climate change.

Among several recommendations, it said the UN's Intergovernmental Panel on Climate Change, paid for by governments including the UK and Netherlands, should in future pay researchers to review the report in more detail.

The report was officially welcomed by the IPCC and scientists who worked on the last assessment report, published in 2007, however only a small number of the "errors" have been corrected. The remaining errors were not accepted by the scientists, said Professor Martin Parry, who was co-chair of the section of the report that was under scrutiny.

"The conclusions are not undermined by any errors, and we'd like that to be the message the world will take," said Parry. "[They found] a very small number of near-trivial errors in about 500 pages [and] probably 100,000 statements. I would say that's pretty good going."

The scientists also rejected the potentially more damaging complaint that the IPCC's Summary for Policy Makers report, which condenses eight chapters on regional impacts to a single page of 32 statements, ignored positive impacts such as the ability to grow new crops in some parts of the world, or opening of shorter Arctic sea routes.

The summary, vetted "line by line" by governments, highlights the biggest impacts on humans and the environment which need political attention, said Parry. Positive benefits tended to be local and relatively small, said Professor David Vaughan of the British Antarctic Survey, a lead coordinating author of the next IPCC assessment.

The agency was asked to examine eight chapters about the regions in the 500-page section on global impacts put together by Working Group II, which itself formed half of the full 1,000-page IPCC assessment.

One "minor inaccuracy" the Dutch panel said it found was an estimate of people in Africa who could be exposed to water stress, which they said should be narrowed from 75m-250m to 90m-220m. However Professor Nigel Arnell, the source of the data, said although the underlying models could have been added differently, to recalculate the total would be to "over-interpret" the data by suggesting a level of accuracy the IPCC does not claim.

As well as the 12 errors, the Dutch reviewers made 23 criticisms of the "quality" of statements. These ranged from failure to explain that forecast water stress and heat deaths also had other causes such as population growth, to pointing out a link to underlying research did not work. Arnell said the IPCC report "repeatedly stresses" its estimates of numbers are a comparison to what would happen if forecast climate change did not happen.

Despite rejecting many criticisms in the Dutch report, the IPCC has employed more reviewers for the fifth assessment, and should consider other changes, including paying scientists to make sure every line of the report is scrutinised before it is published, said Parry.

The Dutch government asked the environment agency to investigate the IPCC report after international controversy about two mistakes in the 2007 assessment: the date by which Himalaya glaciers were expected to melt, and a claim that 55% of the Netherlands is below the sea level. The agency report admits this mistake was based on information it provided and says the real figure was 29%.