Ancient volcanoes and newly minted technology both have a role to play in our climate future, Emeritus Professor Colin Campbell-Hunt writes.
Little by little, the early signs of our future low-carbon world are emerging. A couple have come past my door over the past month.
First, a report from Iceland of a new technique to sequester carbon; that is, to capture it before it is emitted into the atmosphere and then store it somewhere, forever.
Carbon capture and storage (CCS) has to be one of the ways we keep a warming climate within limits.
Even if we stop emitting CO2 completely by 2050 - as we must do to have even a modest chance of keeping within two degrees of warming - we will then have to continue to capture and store carbon for centuries to come.
So far, few CCS technologies have shown great promise.
A particular problem is that once injected underground, the CO2 remains a gas and must be expensively sealed in to stop it leaking out again.
The promising feature of the Iceland experiment is that it literally turns the gas to stone.
It works by injecting a mixture of water and gas (25 tonnes of water for every tonne of gas) into basaltic rock formations, the outflows of ancient volcanoes.
The researchers anticipate that the carbon will react with elements in the basalt to form calcite, a solid mineral.
If it works at scale, the outstanding advantage of this process is that the carbon is then permanently bonded to its location and requires no further oversight.
If you are worrying about all that precious water being used, you are right.
As we know already, water is going to be increasingly scarce in our warming world.
Even at today's prices, the Iceland researchers believe that using water will mean a cost of US$17 per tonne of CO2 processed.
But that is not much above today's price of carbon in New Zealand, and other projects are pursuing the same result without using water.
There are basalt deposits throughout New Zealand, from Northland to Auckland Island and including Timaru and Dunedin, so CCS processing plants may become part of our future low-carbon life.
Second, the electric vehicle roadshow came to town this week, featuring campaigner Chelsea Sexton.
The latest statistics from the International Energy Agency show that New Zealand's CO2 emissions from transport total 12.4 million tonnes.
That's nearly three tonnes, every year, for every man, woman and child in the country.
Transport accounts for 40% of the 30.7 million tonnes of CO2 we emit every year from burning fuel, so a technology that promises to make substantial cuts in vehicle emissions is surely going to be part of our future.
Enter the electric vehicle, or EV, as its delighted owners call it.
The Energy Efficiency and Conservation Authority (EECA) website has an extensive list of the benefits of EVs for the environment and their owners.
Some highlights: 80% less emissions than petrol or diesel (60% less when cost of manufacture is included); fuel cost equivalent to 30 cents a litre of petrol; a fuel source - electricity - that we produce at home from 80% renewable sources, as against imported fossil fuels costing us $8 billion a year; convenience of use, especially in city driving, where 90% of daily travel is less than 90km; just plug the car into your garage power plug overnight and it is ready to go the next morning; effectively zero emission of particulates; a car that is fun to drive (quiet, clean and really quick acceleration); with only 18 moving parts, a car with minimal need of maintenance.
Depending on who you listen to, there are between 1000 and 1500 EVs in New Zealand now, and the number is doubling every year.
Local electricity retailers are installing fast-charge stations that will bring your EV back up to charge in 20-30 minutes.
Dunedin's Delta has installed a fast-charge station in the DCC's Filleul St car park, and charging is free for the first year.
Other businesses are planning national networks of fast-charge stations that will gradually increase the distances we can cover in an EV.
Charge Net has opened a station in Invercargill and plans to open in Gore and Balclutha this year.
Before too long, we will see fast-charge outlets alongside retail outlets so we can charge while we shop.
So far, EV technology can only provide good alternatives for passenger vehicles, and small ones at that.
Mid-size vans and trucks are still to come.
They are limited to about 100km on one charge, which is fine for most city driving, but longer-distance drivers will still need to look for dual-fuel options.
The cars are expensive when bought new, around $70,000, but a pre-loved EV from Japan (where subsidies are used to keep the new price down) will cost you about $20,000 here.
So when the time comes to replace your car, if your car-use fits the EV profile, and you would like to do something to reduce your share of the three tonnes of CO2 emissions per head per year, look up Dunedin EV Owners on Facebook and go for a spin.
Who says we can do nothing to stop a warming world?
- Colin Campbell-Hunt is an emeritus professor with the University of Otago Centre for Sustainability. Each week in this column, one of a panel of writers addresses issues of sustainability.
