Rising sea levels could flood large parts of central Nelson, including the airport, in 100 years, a new climate change report warns.

The report, released yesterday by research company Cawthron Institute, also said Motueka, the Boulder Bank, Trafalgar Park, Waimea Estuary and much of Farewell Spit could be at risk.

It said that unless global emissions were significantly reduced by 2020, many coastal areas and infrastructure could be degraded or destroyed. Ratepayers would have to pay to protect or relocate Nelson community assets.

"The changes in climate expected for the Nelson region over the next century include a rise in temperature [of 2.5C], an increase in annual rainfall and increased frequency and severity of extreme weather events," the report said.

Droughts and severe winds would also increase.

The report showed a 1m rise in sea levels would have water lapping at Nelson Airport, while a rise of 1.9m would flood it.

Warmer temperatures would also cause major problems for Nelson - known as one of the country's sunniest regions.

"It cannot be denied that the prospect of warmer summers and fewer frosty mornings is an attractive one intuitively, but the negative consequences should be considered."

Those consequences included an increase in the number of mosquitoes, blowflies, ants, termites, jellyfish, wasps and other pests.

The report also outlined how the changes would affect the economy and local industries, including forestry, horticulture, fishing and aquaculture and tourism, which generate gross domestic product of about $1 billion.