The report, Climate Change Projections and Impacts for Tairawhiti and Hawke’s Bay, outlines a future worst-case scenario, and alternatively what it could look like if the world takes effective action to reduce greenhouse gas emissions.
It says annual average temperatures are projected to rise between point-five and one degrees by 2040, and between one-point-five and three degrees by 2090. This comes on top of a one-degree increase over the last century.
Hawke’s Bay Regional Council chief executive James Palmer says those increases might not sound much, but they mean heatwaves in the region will become more common, with increases of between 10-20 days by 2040, and 20-60 days by 2090.
Annual rainfall is projected to drop up to 5% by 2040, and up to 15% in parts of Hawke’s Bay by 2090. That will affect rivers in the region, which are looking at a 20% decrease in flow by 2090.
Palmer says that means there will be more droughts, and they’ll be harder to endure.
“It means our agricultural production will likely decrease and the health of our rivers will likely decrease, which will also affect our drinking water supplies,” he said.
Under an extreme worst-case scenario, the coast will be affected by sea level rise of up to point-four metres in 40 years and worsening coastal erosion.
He says rising temperatures will lead to an increase in pests and diseases, which will affect the quality and quantity of fruit and vegetable crops, as well as the productivity of forestry and pasture.
The report predicts that although rare, extreme rainfall will become more severe, leading to more erosion in the hill country and damage to water supply and farmland.
“The few opportunities the report highlights – increased pasture and plant productivity of select plants, less frost damage and longer summers for tourists – are heavily outweighed by the serious consequences we’re looking at,” Palmer said.
Council chair Rex Graham says the report is a push to pick up the pace of climate action.
“This is a scary report that shows how quickly the climate crisis is coming at us,” he said.
“We must do more to make our region more climate resilient, and decrease our greenhouse gas emissions.
“We need to tackle this head on as a region and come together as a community.
While we’re working hard at the regional council to make Hawke’s Bay more resilient to climate change, we need to do so much more as a region to achieve the transformational change required to reduce our environmental footprint and live more sustainably.”
The report was commissioned by Hawke’s Bay Regional Council, Gisborne District Council and Envirolink, and conducted by the National Institute for Water and Atmosphere (NIWA).