How much time do we have?
“Temperature rise to date has already resulted in profound alterations to human and natural systems, bringing increases in some types of extreme weather, droughts, floods, sea level rise and biodiversity loss, and causing unprecedented risks to vulnerable persons and populations.” – IPCC Special Report
“New Zealand’s Paris Agreement target is inconsistent with the Government’s goal of keeping the average temperature increase to within 1.5°C, officials have told ministers. The advice from the Ministry for the Environment was given to Climate Change Minister James Shaw in February and obtained by Stuff under the Official Information Act. Shaw was told the target allows some 85 million tonnes more emissions between 2021 and 2030 than would be compatible with a 1.5°C goal – putting the country over budget by about one year’s current emissions.” – Stuff July 2020
We have run out of time to return our climate to the stability that our global civilization enjoyed for the past several thousand years. The aim now is to cut net emissions to limit the magnitude of impacts. The faster we can do this, the more we can save, and the less we will lose—for ourselves and our children’s futures.
Under the 2015 Paris Agreement, cutting greenhouse gas emissions in half by 2030 might have given the world a 63% chance of staying below 2°C of global average temperature rise, and a 50% chance of staying below 1.5°C.
This is the threshold associated with the most dangerous climate threats and what was agreed by most countries at the time, to keep global warming from surpassing 1.5°C above pre-Industrial levels. These risky odds do not include most feedback loops and non-linear (ie impossible to reverse) tipping points.
Video 1: United Nations Emissions Gap Report 2019
To achieve this, emissions from all sources need to be cut 7.6% every year until 2030. However, emissions continue to rise and the Paris commitments made by many countries, including New Zealand, are falling short (Figs. 1 & 2 and Video 1).
This is in part due to agricultural emissions, which in New Zealand are exempt under our Greenhouse Gas Inventory until 2025, and thereafter will be heavily subsidised (95%) ie, taxpayer dollars will prop up the single largest (47.8%) greenhouse gas emissions sector in NZ (Fig. 3).
Net emissions means gross greenhouse gas emissions from all industrial activities, burning fossil fuels for energy, and agriculture, minus carbon sinks from forestry, changing agricultural to improve soils, and regenerating natural ecosystems. However, instead of declining, global emissions continue to increase each year. Due to reduced transport, Covid-19 has meant a temporary respite of carbon dioxide emissions. However, that has not reduced agriculture emissions in New Zealand and elsewhere. Manufacturing in China has also resurged. Moreover, dangerous tipping points are being breached, which means natural carbon sinks are now becoming sources of methane and carbon dioxide.
References and further reading
- 2020: Gibson; New Zealand’s Paris target too weak for 1.5C – official advice to Govt; Stuff.co.nz
- 2019: Tollefson; The hard truths of climate change—by the numbers Nature special report
- 2015: The Paris Accord
- IPCC: Special Report – Global Warming of 1.5°C