The IPCC's latest special report - Global Warming of 1.5C - has been released at a press conference in Incheon, South Korea.
The report was approved on Saturday following a week-long session in Incheon. It highlights a number of climate change
impacts that could be avoided by limiting warming to 1.5C above pre-industrial levels, including offering some
protection to coral reefs and preventing about 10 centimetres of sea-level rise.
The SMC asked experts to comment on the report.
Associate Professor Bronwyn Hayward, University of Canterbury and a lead author on the IPCC special report, comments:
"In my view, this hard-hitting 1.5 degrees Global Warming Report marks the end of ‘magical thinking’ about climate
"The report is unequivocal, our climate is changing now. These changes are already affecting human wellbeing through
extreme weather events and sea level rise, and risking far-reaching losses including coral reefs and Arctic sea ice.
"For the first time, this IPCC report also places climate change within a social context, it asks: how can we limit climate change and achieve other important related goals of sustainable
development and reducing poverty?
"The report makes clear that without unprecedented cuts to emissions now, we will have fewer opportunities to develop
sustainably and will be required to rely increasingly on unproven, risky and possibly socially undesirable technologies
to remove carbon from the atmosphere in the future.
"But to avoid climate warming above 1.5C, we have to scale up action in unprecedented ways across all sectors of our
economy and everyday life, over the next 10 years."
Warming – why 1.5 degrees?
"The report estimates that temperatures have already risen by 1C higher than pre-industrial averages and that our world
is now warming at a rate of about 0.2C per decade.
"This doesn’t sound like much but if we carry on like this, effectively the world will be warmed 50% more that it has
already experienced, between 2040-50, and some regions will feel the effects of these changes even more severely and
"The report’s also clear that avoiding a warmer future above 1.5C will bring significant benefits for millions of people
who will face significantly reduced risks of flooding, food insecurity and climate stress, including Pacific
"Avoiding a higher than 1.5C warmer future matters to New Zealand in many ways - I want to highlight three:
Implications for New Zealand’s coastal communities
"If the world’s temperatures remain at or below 1.5C the report suggests we could avoid an additional 10 cm of sea level
rise on average, over and above the trajectories we are already committed to by 2100. Here in New Zealand where many of
our cities are coastal, this matters a great deal.
"As Tim Naish’s work shows, 20 to 30 centimetres by 2060 is pretty much given already due to warming from carbon already
accumulated in our atmosphere. This new IPCC report underscores that 1.5 to 2 degrees could trigger rapid melting of the
Antarctic and Greenland with very significant impacts locally for much higher rates of sea level rise over time. At the
very least a world warmed above 1.5 degrees has significant implications for New Zealand national adaptation planning."
Issues raised for New Zealand’s Farming Sector
"The 1.5 report also states that if we want to limit global warming to 1.5 degrees and avoid 'overshoot' we need to make
'deep reductions' in methane – by 35% by 2050 relative to the rates of emission in 2010 and undertake targeted
mitigation of nitrous oxide. Again, this presents New Zealand governments and the farming sector with difficult choices.
We have some tremendous opportunities for reducing methane and nitrous oxide but the need for deep cuts in emissions
raises far-reaching questions about stocking and land use, and signals that we might expect significant shifts in terms
of changing consumer behaviours towards more sustainable diets."
New Zealand’s challenge to achieve climate resilient development
"The report is also clear that current national commitments to emission cuts are insufficient to hold the world’s
climate to below 2 degrees. The report calls for far-reaching transitions across all sectors including how we use
energy, land, urban and infrastructure (transport and buildings), and industrial systems and notes the need for a wide
portfolio of mitigation options that carefully manage development to help communities already struggling, to develop
"The New Zealand government and opposition have already committed to debating a bill to create a New Zealand net carbon
zero by 2050, but making this vision a reality presents tough challenges in a country which has historically relied
predominantly on one policy tool - Emissions Trading - to address climate change.
"The implications of the report are that systemic, sustainable changes are required, for a low carbon future. At the
very least, this includes a wide range of life-altering actions across all sectors of our society and economy if New
Zealand is to have a realistic shot at achieving climate-resilient development pathways which meet the needs of all the
community in the future."
Bronwyn Hayward would also like to acknowledge the efforts of Dr Andy Reisinger, the New Zealand Vice Chair of the IPCC,
and Ministry of Environment officials, Dan Zwartz and Helen Plume who put in many long hours in the intergovernmental
approval process for this Special Report.
Catherine Leining, policy fellow, Motu Economic and Public Policy Research, comments:
"For the past decade, we have kept hitting the ‘snooze’ button on serious climate action. The latest IPCC report is a
serious wake-up call about the environmental, social and economic costs of low and slow ambition. We do not face a
simple binary choice between 1.5 or 2 degrees C when the world is on track for neither target and already experiencing
serious climate change impacts.
"One clear finding from the report is that significant and accelerated emission reductions are needed across the
economy, including methane and nitrous oxide from agriculture. A clear implication is that we will need a predictable
and responsive policy framework for adjusting our course, speed and distribution of costs as we progress. Policy
uncertainty is toxic for low-emission investment.
"For New Zealand, effective emission pricing must be a key part – but not the only part – of that framework. We also
need policies to support those sectors and communities who will find it most difficult to adjust, as well as durable
processes and institutions for cross-sector engagement and independent advice. Above all, we will need to sustain social
and cross-party consensus on how much we stand to gain, and how we choose to spread the costs, from bolder, faster
Dr Jonny Williams, climate scientist, NIWA, comments:
"The IPCC special report on the effects of increasing average world temperatures by 1.5C above pre-industrial levels is
realistic, with the authors recognising that maintaining temperatures below 1.5 degrees will be challenging, but
certainly not impossible.
"For this reason, the report also considers the differences between the effects of climate change at 1.5 and 2 degrees
of warming as well as the potential need to actively remove greenhouse gases from the atmosphere to reduce their warming
"It’s important to emphasise here that although many people are familiar with global warming, this rising air
temperature is just one example of climate change’s effects on our planet. Other effects which are explored in the
report include ocean acidification and the impact of rising ocean temperatures on coral reefs and fisheries, and sea
"When it comes to the risks to humans from climate change, sadly it is often the people who are least able to take
action who will be affected the most. These groups include those who are dependent on the above-mentioned fisheries for
their livelihoods and those who may be displaced from their homes due to sea level rise.
"The report has gone through an extensive and lengthy peer review process and represents the current state of scientific
understanding of where we are now and where we might be going in the future. It does not lose sight of the human side of
the equation however and makes frequent reference to the UN’s Sustainable Development Goals which were highlighted
frequently by former Prime Minister Helen Clark during her time as Administrator of the United Nations Development
Conflict of interest statement: Dr Williams was a peer reviewer of the report.
Professor James Renwick, Victoria University of Wellington, comments:
"The report says roughly what I expected it to, but it still makes for sobering reading. We are currently living with 1C
of global warming and we’re seeing effects already in extreme events and impacts on ecosystems and societies worldwide.
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.
"This report makes a compelling case for rapid decarbonisation, starting now. If we want to save even a fraction of
unique ecosystems such as the Great Barrier Reef, we cannot afford two degrees of global warming.
"However, while stopping at 1.5C is still physically possible, it would require huge political and social commitment
from all countries. The world would need to reach zero carbon by 2050, with a 50% reduction between now and 2030. Given
the past trajectory of global emissions of greenhouse gases (nearly a doubling in the past 30 years), this represents a
truly heroic and unprecedented effort to turn the global economy around. Are the governments, the businesses, and the
people of the world up to it?"
Dr Jim Salinger, Deputy Editor Climatic Change Journal and former IPCC lead author, comments:
"The latest IPCC report is the most significant of all those to date because the difference between the impacts of 1.5°C
and 2.0°C is earth-shattering. For example, coral reefs would decline by 70-90 per cent with global warming of 1.5°C,
whereas virtually all (> 99 per cent) would be lost with 2ºC. Species loss and extinction are projected to be
significantly lower at 1.5°C of global warming compared to 2°C.
"The report notes globally, human activities are estimated to have caused approximately 1.0°C of global warming above
pre-industrial levels, with a likely range of 0.8°C to 1.2°C. Global warming is likely to reach 1.5°C between 2030 and
2052 if it continues to increase at the current rate.
"For New Zealand, temperatures have increased by 1.2°C between 1867 and 2018 as shown in the diagram below with this
year heading to be one of the warmest ever.
[caption id="attachment_34941" align="aligncenter" width="603"] New Zealand annual temperature 1867 – 2018 compared with the 1867-1900 average (blue bars). The dashed line (red) shows
the trend. Source: Dr Jim Salinger.[/caption]
"With a global average temperature rise by 2ºC above pre-industrial values, then around 400,000 of the species that we
know could go extinct, the numbers for 1.5°C would probably be about a third to half this number.
"There are also substantial implications for New Zealand’s future greenhouse gas (GHG) emissions reductions, especially
methane (CH4) to keep warming at about 1.5°C. Carbon dioxide emissions reductions must commence at 2020 and reduce by
about half by 2030. For 2.0°C, this must be achieved by 2040.
"For 1.5°C starting at 2020, methane must be halved by 2040 to keep warming at about 1.5°C, when carbon dioxide must be
about a quarter of its 2020 emissions. Thus the 1.5°C requires immediate reductions in all greenhouse gas emissions. New
Zealand does not have the luxury in delaying its agricultural methane emissions to play its part to achieve the 1.5°C