If the world continues to emit greenhouse gasses it will lock in a further 3C of global warming and 10m of sea level rise, according to a professor.
Victoria University professor James Renwick was a keynote speaker at the Just Transition Community Conference in New Plymouth today.
He said the situation was dire.
"There's been a lot of talk about a climate emergency lately and it really is an emergency situation.
"If the globe is going to meet the Paris Agreement targets, the 1.5C warming above pre-industrial or certainly less than 2C less than pre-industrial levels, then we have to reduce emissions of greenhouse gases and certainly carbon dioxide urgently.
"So we're talking about getting ... back to zero by 2050 and that's a huge ask at the moment. Last year saw the highest emissions globally on record and emissions have been going up, up and up for the past 30 years."
Prof Renwick said if emissions carried on as they were for more than 20 years or through to 2050, it would be catastrophic.
"We'd be on track for 3C of warming globally. That's three more degrees of warming, we've already had one. And that would lock in the loss of the West Antarctic Ice Sheet and a good part of the Greenland Ice Sheet and probably result in 10m of sea level rise.
"It would change rainfall and temperature extremes to the point where you'd see major crop failures. Maybe a 30 percent reduction in grain production around the world so [there would be] major food shortages and food security issues.
"Locking in many metres of sea level rise - that would happen over hundreds of years - we'd be redrawing the map of the world. We'd be displacing hundreds of millions of people, if not billions. It would be, you know, mayhem on a scale that humanity never had to deal with before."
Prof Renwick said the government's Zero Carbon Bill was a step in the right direction but it was a case "of all hands to the pump" if a catastrophe was to be avoided.
Climate Justice Taranaki held the conference to offer grassroots organisations an opportunity to have a say in the move to a low-carbon economy.
Climate Justice Taranaki researcher Catherine Cheung said the government-sponsored $400-a-ticket Just Transition Summit held in New Plymouth last month was very business driven.
"Businesses surely do have a role in transitioning off fossil fuels, but we feel really the community needs to be driving the process. It needs to be a lot more community focused when we are talking about reducing emissions and building a more sustainable and resilient community for our people here."
Today's free event featured 16 speakers, ranging from experts on climate change and sustainable energy sources, through to unionists, farmers and a youth panel.
Bioenergy Association chairman Brian Cox, one of the keynote speakers, said the carbon-neutral energy source had the potential to meet 27 percent of New Zealand's energy needs by 2050.
Mr Cox said many bioenergy technologies were already proven.
"The organic material in trees or our waste streams is an ideal feed source for making a whole range of products, which will replace those that are currently produced by petroleum.
"These could be in the form of a gas, often referred to as biogas, and that can be used in vehicles, for heating, for making electricity or making other materials or products."
Mr Cox said bioenergy could be used in a "circular economy" on Taranaki dairy farms where effluent could be used to generate gas to fuel the business.
The region's background in oil and gas could also put it at the forefront of using bioenergy to develop advanced liquid fuels for transport, he said.
"Taranaki is rich in the biomass coming through a whole range of sources, and with the expertise and competence that is in Taranaki from the petroleum industry, it's about applying that to how to extract and divert that biomass into one of those fuels."
Mr Cox said bioenergy should be one focus of a new $27 million clean energy research centre the government announced would be set up in Taranaki.
Ms Cheung said it was hoped that ideas that emerged during the conference would feed into Venture Taranaki's 2050 Roadmap.