Earth’s atmosphere has more carbon in it than at any point in more than three million years.
The amount of carbon in the atmosphere is directly correlated with the average temperature.
That is why we are living through a climate change crisis.
How do we know how much carbon is in the atmosphere? Because we count it.
In New Zealand, we’ve been tracking the CO2 levels of the air at the Baring Head lighthouse near Wellington since 1970.
Air samples are collected, then analysed.
If a single sample was broken into a million parts, 407 of them would be carbon dioxide (CO2).
That is the highest number ever recorded.
We all emit carbon dioxide every day.
It’s called breathing.
In a year, we each exhale about 400kg of CO2. This isn’t a big contribution to carbon emissions.
We typically each do more than sitting around breathing, however.
New Zealand has a bigger problem than the carbon each of its people create.
We also produce other greenhouse gases, most notably, a lot of methane from the agriculture industry.
This hangs around in the atmosphere for a lot less time than CO2, but it’s a much more powerful warmer.
New Zealand, a small nation, does a lot of agriculture.
42 per cent of New Zealand’s land is used for beef, sheep and dairy farming.
So we end up as the 21st worst greenhouse gas emitter, per capita, in the world.
This represents 0.17 per cent of the world’s greenhouse gas emissions.
Most CO2 is naturally absorbed through what is known as carbon sinks - primarily forests and oceans.
The carbon dioxide exhaled by 30 people in a year, for example, would be comfortably absorbed by one rugby field-sized area of forest.
But our planet’s capacity for soaking up carbon has long since been exceeded. The excess is now building up in the atmosphere.
Which brings us back to those 407 parts of carbon per million particles of air.
For most of the last 2000 years, that figure remained between 270 and 290 ppm. It has skyrocketed since the industrial revolution.
Over the last 800,000 years, it went as low as 150 parts per million during the ice age, and as high as 300 ppm.
This carbon problem is getting worse, not better.
Half of the industrial era growth has occurred since 1995.
Atmospheric CO2 is currently climbing at close to 3 ppm each year, and rising. Earth’s average temperature has already increased by 1 degree.
A 2 degree increase is expected to happen when there are 450 ppm of CO2 in the atmosphere.
The Paris Accord set a 1.5 degrees limit on average temperature rise.
But right now, we’re on track to go over the 1.5 and 2 degrees increase thresholds.
If emissions aren’t drastically reduced, it’s virtually guaranteed the world is in for a rise of more like 4 degrees.
This would mean vast tracts of South America, Africa, and Asia, including all of Bangladesh and Indonesia, would become uninhabitable due to drought.
New Zealand as one of the few habitable areas on the planet, would likely become overcrowded, under constant threat of flood and cyclone, and increasingly infested by flies and other insects.
REPORTING Joel MacManus
DESIGN AND LAYOUT Kathryn George
EDITOR John Hartevelt
Special thanks to Dr James Renwick
