The IPCC Special Report on Global Warming of 1.5ºC: What you need to know

Australia Publication October 2018

On October 8, 2018, the Intergovernmental Panel on Climate Change (IPCC) released its Special Report on Global Warming of 1.5ºC (Special Report) (see here).

The Special Report synthesizes the impacts of global warming of 1.5ºC above pre-industrial levels and related global greenhouse gas emission pathways from research across the global scientific community. The context of the report is to strengthen the global response to the threat of climate change, sustainable development and efforts to eradicate poverty.1

The Special Report not only provides vital guidance for upcoming international climate change negotiations in December; it also informs business and government decision-making around climate risk.

Further, noting the Hague Court of Appeal’s decision on 9 October 2018 to uphold the ruling in Urgenda Foundation v The State of Netherlands (Urgenda), the Special Report is likely to play a strong evidentiary role in future litigation relating to the impacts of climate change.


The IPCC is the leading world body for assessing the science related to climate change impacts, risks and responses and has been instrumental in driving action on climate change. 

Following the adoption of the Paris Agreement at COP21 in 2015, the IPCC was invited to produce the Special Report on the impacts of global warming of 1.5ºC. This Special Report is one of three Special Reports to be released by the end of 2019 along with a Methodology Report to refine the 2006 IPCC Guidelines for National Greenhouse Gas Inventories. The IPCC’s Sixth Assessment Report will be published in the first half of 2022. 

The Special Report is highly relevant to commitments in the Paris Agreement to cut greenhouse gas emissions with a view to ‘holding the increase in the global average temperature to well below 2°C above pre-industrial levels and pursuing efforts to limit the temperature increase to 1.5°C above pre-industrial levels’ (see our earlier update on the Paris Agreement here).2

The 24th Conference of the Parties to the United Nations Framework Convention on Climate Change (COP 24) is scheduled to meet in Katowice, Poland in December 2018 to finalise the rules which underpin the implementation of the Paris Agreement and the Special Report will play a strong role in negotiations.

Findings of the Special Report 

The Special Report states that human induced warming has already reached about 1°C above pre-industrial levels. If the current warming rate continues, the world is expected to reach human induced global warming of 1.5°C around 2040. 

The Special Report highlights a number of climate change impacts that could be avoided by limiting global warming to 1.5°C compared to 2°C, or more. 

For instance, global sea level rise would be 10 cm lower with global warming of 1.5°C compared with 2°C by 2100. An Arctic Ocean free of sea ice in summer would occur once per century with a temperature rise of 1.5°C, compared with at least once per decade with 2°C. Coral reefs would decline by 70-90 percent with global warming of 1.5°C, whereas larger losses (> 99 percent) would occur at 2ºC. Notably for Australia, this will mean the difference between the partial survival of the Great Barrier Reef and its destruction. 

The report finds that limiting global warming to 1.5°C is possible but would require rapid and far-reaching transitions in energy, land, urban and infrastructure (including transport and buildings), and industrial systems. 

These transitions are unprecedented in terms of scale, but not necessarily in terms of speed. Deep emissions reductions would be required in all sectors, with a wide portfolio of mitigation options and a significant upscaling of investments in those options. 

In particular, the Special Report finds that for energy pathways limiting global warming to 1.5°C with no or limited overshoot

  • Renewables are projected to supply 70–85 per cent of electricity in 2050.
  • Nuclear and fossil fuels with CO2 capture and storage are modelled to increase.
  • Use of CO2 capture and storage would allow the electricity generation share of gas to be approximately 8% of global electricity in 2050.
  • Coal would be reduced to close to 0% of electricity.
  • CO2 emissions from industry are projected to be about 75–90 per cent lower in 2050 relative to 2010, as compared to 50–80 per cent for global warming of 2°C.
  • Industry would have engaged in combinations of new and existing technologies and practices, including electrification, hydrogen, sustainable bio-based feedstocks, product substitution, and carbon capture, utilization and storage. 

Solar energy, wind energy and electricity storage technologies have substantially improved over the past few years signalling a potential system transition in electricity generation. In support of this finding, the Special Report states that total annual average energy-related mitigation investment for the period 2015 to 2050 in pathways limiting warming to 1.5°C is estimated to be around 900 billion USD. 

In addition, the Special Report finds that for urban and infrastructure pathways limiting global warming to 1.5°C with no or limited overshoot

  • Urban and infrastructure electricity share of energy demand in buildings would be about 55–75 per cent in 2050 compared to 50–70% in 2050 for 2°C global warming.
  • The share of low-emission final energy in the transport sector would rise from less than 5 per cent in 2020 to about 35–65 per cent in 2050 compared to 25–45 per cent for 2°C global warming. 

The Special Report finds that for land pathways limiting global warming to 1.5°C with no or limited overshoot

  • Transitions in global and regional land use scale would, depending on the pursued mitigation portfolio, be projected to involve the conversion of 0.5–8 million km2 of pasture and 0–5 million km2 of non-pasture agricultural land for food and feed crops into 1–7 million km2 for energy crops and between a 1 million km2 reduction to 10 million km2 increase in forests by 2050 relative to 2010. This would however create challenges for sustainable management of competing demands on land and mitigation measures would be required such as ecosystem restoration.
  • CO2 removal measures would include afforestation and reforestation, land restoration and soil carbon sequestration, bioenergy with carbon capture and storage, direct air carbon capture and storage, enhanced weathering and ocean alkalinisation. 

Notably, economic, institutional and socio-cultural barriers may inhibit transitions, depending on national, regional and local circumstances, capabilities and the availability of capital. 

What is the impact of the Special Report? 

Although the Special Report appears to have received limited support from the Australian Federal government to date, it can be expected to have an impact in the development of climate policies across local and state government in the next couple of decades. For Australia, these transitions will have their own challenges, particularly in the transportation, agricultural and industrial sectors which, to date, have received little policy attention from the Federal government – the primary focus being on the energy sector. 

In addition to its importance in potential climate litigation, the findings in the Special Report provide a strong signal for government and business that transitions in energy, land, urban environment, infrastructure and industrial systems that enable the limiting of global warming to 1.5°C will be required. 

The findings are also expected to guide the COP24 international negotiations as well as the development of government climate change policies and business investment and operations decisions globally. 

We will be reporting on the outcome of COP24 later this year, and we invite you to visit our COP page for further information here

What is the relevance of the Special Report in the context of the Urgenda appeal decision? 

It is also worth noting that on 9 October 2018 the Hague Court of Appeal upheld the Netherland’s District Court’s ruling in Urgenda (see unofficial English translation from the Court here). 

The District Court decision in Urgenda found that the Dutch constitution reflects a duty of care to address climate change and that the Dutch government must do more to avert the imminent danger of climate change. See a link to our earlier climate change litigation update including a case note on the Urgenda District Court decision here

The appeal decision found, in upholding the District Court decision, that by failing to reduce greenhouse gas emissions by at least 25 per cent by end-2020, the Dutch government was acting in contravention of its duty of care under Articles 2 and 8 of the European Convention on Human Rights, which protect the right to life, private life, family life, home and correspondence.3

Among other things, the Hague Court of Appeal considered the IPCC’s Fourth and Fifth Assessment Reports and found that a sufficient causal link can be assumed to exist between Dutch emissions and the effects of global climate change. 

While the Urgenda decision is not binding on other jurisdictions, it is a landmark case that is likely to influence other judicial systems noting that similar proceedings have been filed around the world in Norway, Pakistan, Colombia, Switzerland, and before the European Union.4

The Special Report, synthesized from thousands of academic studies around the world, provides strong evidence on the impacts of climate change at 1.5°C global warming compared to 2°C and is likely to play a strong evidentiary role in any future climate litigation.



IPCC, ‘IPCC Press Release - Summary for Policymakers of IPCC Special Report on Global Warming of 1.5ºC approved by governments’ (2018/24/PR, 8 October 2018) <>.


Paris Agreement, Article 2(1)(a).


Urgenda Foundation v. Kingdom of the Netherlands [2015] HAZA C/09/00456689 (Unofficial English Translation from the Court).


Dena Adler, ‘Dutch Court Upholds Landmark Urgenda Decision Requiring Dutch Government to Reduce Greenhouse Gas Emissions’ (Columbia University Sabin Centre for Climate Change Law, Climate Law Blog, 9 October 2018) <>.



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