Climate change effort made easy

Massey University's Professor Robert McLachlan takes an interest in climate change. PHOTO/ FILE

It's time to stop investing in oil and gas infrastructure and electrify everything, Robert McLachlan says.

That was his one-sentence recipe to slow climate change, given in a talk to about 45 people in Whanganui last week.

Mr McLachlan is a professor of applied mathematics at Massey University. He researches the computer algorithms used to model climate change, and following its progress has been a long term hobby.

He's no "collapsatarian" - not pushing the message that humans will be extinct in 10 years. He talked about easy ways to cut carbon emissions - ways that don't involve radical changes to the way we live.

He said New Zealand had lots of opportunity to reduce emissions, since it's not very hot or cold and has lots of renewable energy options.

When it comes to transport, he said all cars should be electric. He bought an electric Nissan Leaf himself and said it was better and cheaper than the fossil fuel burning version.

"It's unbelievably nice. Completely silent, with unbelievable acceleration."

It costs 1.7 cents/kilometre to run, compared to 13 cents for a petrol driven car.

It saves the emission of 2 tonnes of climate-changing carbon di oxide a year. Most New Zealanders emit 18 tonnes a year, and we need to reduce that to 1.5 ot 2 tonnes each a year.

Electric trucks and buses are becoming available, and Air New Zealand is in the process of electrifying all its ground operations.

Some of New Zealand's electricity is produced by burning coal and gas, which emits 4,000,000 tonnes of carbon a year. Solar and wind production are getting cheaper.

Power companies Meridian, Mercury and Trustpower don't burn fossil fuels to generate electricity. Genesis and Contact do.

Mr McLachlan changed his provider to Ecotricity, just by sending an email. The change saved him being responsible for the emission of one tonne of carbon a year.

A friend of his spent $8500 on 3kW solar panels. Between the money he saves by using that electricity and the money he earns by selling some back to the grid he has made a seven per cent return on his investment and saved the emission of 0.2 to 0.4 tonnes of carbon.

Businesses and big box stores can make the same gains by installing solar panels.

An 185sqm Kiwi house uses 12000kWh of heating a year. Burning diesel or gas for heating emits 2.4 tonnes of carbon a year. Using a heat pump, burning wood pellets or chips or using a log burner reduces emissions to 0.3 tonnes.

On the food front, cutting beef and lamb from the diet saves a lot of climate-changing gas emission - that gas being methane, from ruminant animals.

Chicken and pork make for less emissions. Vegetarian and vegan diets cause even fewer.

The world's carbon emissions have stabilised and decreased slightly since 2014. Now we need ways to suck that carbon out of the atmosphere, Professor McLachlan said. As trees grow they store carbon in their wood.

"If everybody in the world planted 40 trees we would be saved from climate change."

One hectare of growing trees stores eight tonnes of carbon a year.

"We have enough marginal land in New Zealand to plant trees and suck up all our carbon we are emitting, but there's not policy incentive at the moment," Professor McLachlan said.

Looking around at his talk last week, he noticed the audience was mainly older people. He's looking for ways to get the message out to people aged 20 to 50.

All the slides that went with his talk are on his internet website.