'Life-altering' changes needed to avoid the worst of climate change
Monday, 8 October 2018
Life as we know it will need to change if the world is to limit global warming to a level that will prevent its worst effects - and it will need to change quickly.
A landmark global report about limiting global warming to 1.5C above pre-industrial levels found it remained technically possible, but would require 'rapid, far-reaching and unprecedented changes in all aspects of society'.
Not only would all countries need to make more aggressive cuts to emissions than ever before, it would likely require removing carbon dioxide from the atmosphere, through unproven and potentially risky technology.
The findings could have implications for New Zealand, particularly around the role industries such as farming and tourism will need to play in achieving such drastic cuts.
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The Intergovernmental Panel on Climate Change (IPCC) report, released on Monday, had 91 co-authors and contained more than 6000 scientific references. It was approved by representatives of 190 countries, and is the most comprehensive analysis of the steps required to limit warming to 1.5C to date.
The world has already committed to keeping warming 'well below' 2C through the Paris Agreement, which also included a more aspirational goal of 1.5C.
The door to achieving that goal remained ajar but was quickly closing, the new report found, and would require severe cuts to emissions across all parts of society almost immediately to be feasible.
The world has already warmed around 1C above pre-industrial levels, the report said, and the effects were already apparent through increasingly severe weather events like storms and wildfires.
To achieve 1.5C, the world as a whole would need to cut carbon emissions around 45 per cent by 2030, and reach 'net zero' by around 2050. Even then, carbon dioxide may need to be removed from the atmosphere.
The report's greatest implication for New Zealand is likely its findings around methane. The world would need to cut methane emissions by around 35 per cent before 2050, which would have a severe impact on New Zealand's economy if matched here.
The report's only New Zealand lead author, Dr Bronwyn Hayward of the University of Canterbury, said limiting warming to 1.5C would require 'life-altering' changes within the next 10 years.
'There isn't an easy way to do this,' she said.
'If we don't make these really difficult, unprecedented cuts now, we will have fewer options for sustainable development and for our economies, and we'll be forced to rely on these risky, unproven, and potentially socially undesirable forms of carbon removal.'
New Zealand had some advantages, she said - it already had a high proportion of renewable energy, which was a major issue for other countries.
But New Zealand was unusual in that methane made up a sizeable proportion of its emissions, due to pastoral agriculture.
'While we've got some really great farming sector innovations, that's a really significant cut and it will require far-reaching policy choices,' Hayward said.
'We really need to have some wide-ranging, life-altering changes across our society and our economy, otherwise we won't have a realistic shot at creating what we call in this report climate resilience development.'
WHY 1.5C?
The difference between a world that is 1.5C warmer and one that is 2C warmer would be significant, the report said. It could be the difference between a world that is recognisable and one that is not.
The higher level of warming would expose hundreds of millions more people to climate-related risks, the report said, and come with much larger environmental impacts.
It is expected that between 70 and 90 percent of coral reefs will die in a world that is 1.5C warmer; If it rose to 2C, virtually all - more than 99 per cent - of coral reefs would be destroyed.
Hundreds of thousands more species would be at risk of extinction under 2C, and the global food supply would restrict due to lower crop yields, and water scarcity would increase.
If warming was capped at 1.5C, sea level rise would be about 10cm lower on average by 2100, saving millions of people from exposure to coastal risks. The lower temperature would be more likely to prevent the collapse of the Antarctic ice sheet, which would cause much more significant sea level rise beyond 2100.
Under current commitments, the world is on track for 3C or 4C of warming.
WHAT NEXT?
The decisions made within the next 10 years will be vital in knowing if warming can be kept to 1.5C.
The world has a set 'budget' for how much carbon dioxide can be emitted, which, at the current rate, will be used up quickly.
'If we want to keep a two-thirds chance of keeping temperatures within 1.5C, the carbon budget we have [will be] used up within 10 to 14 years' said Professor Mark Howden of Australia National University, one of the report's lead authors.
'We haven't got much time to limit our greenhouse gas emissions.'
He said doing so was not impossible, but 'would require major transitions in many aspects of society'.
The report's findings broadly echoed what New Zealand's climate scientists had been arguing - that severe cuts were needed quickly to avoid the worst effects of climate change.
'[T]he difference between the impacts of 1.5C and 2C is earth-shattering,' said Dr Jim Salinger, a former IPCC lead author.
A key issue for New Zealand was the need for methane reduction, which meant it could no longer delay reductions in agricultural emissions.
'The 1.5C requires immediate reductions in all greenhouse gas emissions,' Salinger said.
'New Zealand does not have the luxury in delaying its agricultural methane emissions to play its part to achieve the 1.5C target.'
Reducing emissions to the required level would involve a 'truly heroic and unprecedented effort', said Professor James Renwick of the Victoria University of Wellington.
'More warming, even half a degree, means more and bigger impacts, but it is clear that a 1.5C world would be a lot more manageable and recognisable than a 2C world,' he said.
'[W]hile stopping at 1.5C is still physically possible, it would require huge political and social commitment from all countries.'
He said global greenhouse gas emissions had doubled over the last 30 years, and the report made a compelling case for rapid decarbonisation.
Although New Zealand was already considering a 'net zero' economy by 2050, there remain questions around how to get there.
Bronwyn Hayward said it would require more policy tools than previously considered: New Zealand had largely relied on an Emissions Trading Scheme, but it may not be enough.
'It's not just a nice-to-have, the 1.5C versus 2C,' she said.
'It will protect millions of people, particularly in terms of sea-level rise, when we look at where our communities are distributed globally.
'It's not enough to do a few key policy changes in a few sectors. We are really looking at what we call systemic or system-wide change to try and create more climate resilience for communities.'