WELLINGTON - Predictions of global climate change made to a United Nations-organized panel more than 20 years ago have proved to be accurate, a New Zealand-US academic study has found.

The study compared predictions of global temperature rises to 2030 from the first Intergovernmental Panel on Climate Change (IPCC) Assessment Report published in 1990, with global climate change data gathered over the past 20 years.

Authors Professor David Frame, director of the New Zealand Climate Change Research Institute at Victoria University, and Dr Daithi Stone, of the Lawrence Berkeley National Laboratory in California, found the global climate was responding largely as predicted by the first IPCC report.

Two decades later, data showed the actual global mean surface temperature increase was 0.35 to 0.39 degrees Celsius, which was in reasonable agreement with the 1990 predictions, Frame said in a statement.

This was in spite of unforeseen climate-altering events, such as the eruption of the Philippines' Mount Pinatubo in 1991, the collapse of the Soviet bloc industry in the 1990s, and the recent rapid, fossil-intensive growth in economies such as Asia.

They concluded that natural variability alone seemed highly unlikely to account for recent changes, even if the forecasting systems significantly underestimated natural variations.

Frame said a sufficient period had elapsed since the 1990 predictions to allow for a scientific evaluation of them.

"What we've found is that these early predictions seem pretty good, and this is likely due to the climate responding to concentrations of greenhouse gases in the earth's atmosphere at a rate broadly in line with what scientists in 1990 expected," he said.

Frame is also one of the lead authors for the IPCC's fifth Assessment Report.

The IPCC was established by the United Nations Environment Program and the World Meteorological Organization in 1988 to provide a clear scientific view on climate change and its potential environmental and socio-economic impacts.