An international panel of scientists has issued a bleak statement on climate change, saying it's extremely likely that human activity has been the dominant cause of global warming since the mid-20th century.
The Intergovernmental Panel on Climate Change (IPCC) released its first report in six years at a meeting in Sweden on Friday evening (NZT).
More than 250 authors from 39 countries contributed to the report about the physical science basis for climate change.
They collected and assessed the latest science on climate change, rather than doing any research themselves.
The report found that continued emissions of greenhouse gases will cause further warming and changes in all components of the climate system.
"Limiting climate change will require substantial and sustained reductions of greenhouse gas emissions," the report said.
James Renwick, Associate Professor at Victoria University's School of Geography, Environment and Earth Sciences, says ongoing climate change will bring significant changes to New Zealand and its neighbours in the Pacific.
"By the end of the century, extreme heavy rainfalls are likely to become more intense and more frequent in many places while at the same time the risk of drought is set to increase substantially, notably in the east and north of New Zealand," Dr Renwick said.
"An increased frequency of high temperature extremes, and fewer cold extremes, is virtually certain almost everywhere."
Tim Naish, Director of Victoria University's Antarctic Research Centre, says the volume of polar ice sheets and glaciers will continue to decrease, contributing to rising sea levels.
The report suggests that many aspects of climate change, including polar ice sheet melt and sea level rise, will continue for centuries, even if carbon dioxide emissions were stopped, Professor Naish said.
Green Party climate change spokesman Kennedy Graham says the report shows that urgent action needs to be taken.
"The IPCC has delivered a stark message: the climate is changing and we need to immediately reduce our greenhouse gas emissions dramatically to prevent runaway warming," he said.
World Wildlife Fund NZ head of campaigns Peter Hardstaff said the report was a wakeup call for New Zealand.
"The government should cut its $46 million of fossil fuel subsidies, and look at how it can support investment in renewable energy.
"The NZ Superfund and ACC also need to divest the over $1 billion dollars of public money that they have invested in fossil fuels," he said.