1.5°C temperature limit - key facts


Since 2009 over a hundred Small Island Developing States, Least Developed Countries and many others have been calling for limiting global temperature rise to below 1.5°C above pre-industrial levels. Placing the 1.5°C limit alongside the legally binding goal to hold global temperatures “well below 2°C above pre-industrial levels” in the Paris Agreement was a major victory for vulnerable countries. This page is an information pool for material around the 1.5°C temperature limit. It covers these questions:

  • Why 1.5°C? Science, impacts and risks
  • What will it take to limit warming to 1.5°C?
  • What are the emissions reduction targets and 1.5°C pathways?

Sea level legacy: 20cm more rise by 2300 for each 5-year delay in peaking emissions
Peaking global CO2 emissions as soon as possible is crucial for limiting the risks of sea level rise, even if global warming is limited to well below 2°C. A study now published in the journal Nature Communications analyses for the first time the sea level legacy until 2300 within the constraints of the Paris Agreement.

Recent past shows half a degree of warming means more extreme weather
Observational records show that half a degree increase in global temperature in the recent past has resulted in substantial increases in extreme weather events.

New research confirms feasibility of 1.5°C
A recent research conference in Brussels, as part of the ADVANCE project, revealed a range of 1.5°C scenarios derived from a larger variety of climate models. These results are an important milestone in light of the implementation of the Paris Agreement that enters into force on November 4.

IPCC Special Report on 1.5°C
The Intergovernmental Panel on Climate Change (IPCC) has just approved the outline of the special report on the 1.5°C temperature limit – here’s what it will contain.

We can limit global warming to 1.5°C if we do these things in the next ten years
The latest Climate Action Tracker report looked at major emitting sectors and at what can be done – and how fast – to come up with a list of the most important things to do in the next decade to bend the emissions curve downwards. Bill Hare and Niklas Höhne talk about some of these key steps and the progress to date.

For most vulnerable, 1.5°C warming limit is critical: above it, climate impacts rise rapidly
A study by Schleussner et al. 2015 Differential climate impacts for policy-relevant limits to global warming: The case of 1.5°C and 2°C analyses the differences in impacts the world would face at 1.5°C and 2°C in a comprehensive and comparable way for the first time. The study provides an analysis of 8 relevant biophysical impacts, highlighting key differences both globally and in hot-spot regions.

Global warming reaches 1°C above preindustrial, warmest in more than 11,000 years
Global mean warming reached 1°C above preindustrial for the first time. It is a signal from the climate system that time is running out if we are to be able to reduce emissions fast enough so as to hold warming below 2°C, and ultimately below 1.5°C by 2100.

1.5°C long-term temperature limit in the Paris Agreement

Climate Analytics Input into the Talanoa Dialogue, submitted on 3 April 2018
This input summarises scientific findings relevant to the Talanoa Dialogue and the 1.5°C temperature limit in the Paris Agreement. The structure follows the guiding questions the Dialogue.

Science and policy characteristics of the Paris Agreement temperature goal
This peer-reviewed paper led by Climate Analytics presents an analysis of the scientific and policy aspects of the 1.5°C temperature limit in the Paris Agreement’s long-term temperature goal. It gives examples of discernible differences in impacts between 1.5 °C and 2 °C warming, assesses compatible emissions pathways characteristics and identifies key elements of a post-Paris science agenda.

Why 1.5°C? Science, impacts, risks and benefits

“Because the Ocean” – achieving the Paris Agreement 1.5°C temperature limit
Ocean systems are particularly vulnerable to climate change, and there is already clear evidence for loss and damage inflicted by climate change on ocean systems. This briefing provides an overview of the latest science on key risks for ocean systems including from sea-level rise, ocean acidification and impacts on coral reefs and other marine and coastal ecosystems.

In the observational record half a degree matters
This commentary in journal Nature Climate Change discusses how evidence from the observational climate record provides useful guidance in discriminating the climate impacts of half-degree warming increments, which is high on the science agenda since the adoption of the 1.5°C temperature limit in Paris Agreement. You can read a blog post about the findings of this study here.

The Low Carbon Monitor 2016
This United Nations Development Programme report, commissioned by the Climate Vulnerable Forum, focuses on the benefits and opportunities of limiting warming to 1.5°C, as enshrined in the Paris Agreement, in terms of economic growth, employment, avoided climate impacts, energy security, access and imports and health. You can download the fact sheet with key messages of the report here.

Differential climate impacts for policy-relevant limits to global warming: the case of 1.5 °C and 2 °C

This peer-reviewed study identifies substantial differences in climate change impacts between 1.5°C and 2°C global average temperature rise by 2100. Also see the briefing note on the key findings of this study.

1.5°C risks and feasibility – key points

This fact sheet provides key points on risks to ecosystems, food security and sustainable development associated with 1.5°C warming. It also provides responses to arguments commonly made against 1.5°C and provides the scientific evidence for each point made.

Is it possible to return warming to below 1.5˚C within this century?

This briefing comments on the feasibility of holding warming below 1.5°C within this century and provides information on selected climate risks at 1.5°C, 2°C and 4°C warming.

Implications of the 1.5°C limit in the Paris Agreement for climate policy and decarbonisation

This report, commissioned by the Climate Institute in Australia, examines the impacts on Australia of limiting global temperature rise to 1.5°C and 2°C, and to provide estimates of the global carbon budgets associated with achieving these temperature limits.

Climate Impacts at 1.5°C and 2°C – A Pacific Perspective

This is short summary the key climatic risks for the Pacific region at 1.5°C and 2°C warming.

The 1.5°C temperature limit in the Paris Agreement and 2016 temperature records

This briefing provides clarity on how long term temperature limits are to be understood in the context of short term natural variability.

Who is concerned about 1.5°C?

A total of 104 countries called for the Paris agreement to limit warming below 1.5°C. These countries account for about 9% of global greenhouse gas emissions and about 23% of global population in 2010. This is more than at Copenhagen in 2009 where a total of 101 countries, accounting for 5% of global energy and industry related CO2 emissions and about 23% of global population in 2005 called for global temperature to stay below 1.5°C.


The Alliance of Small Island States (AOSIS) and Least Developed Countries (LDC) Group called the legal objective of the Paris agreement to include the 1.5°C limit and for the agreement to be ambitious, legally binding, dynamic with 5 year commitment cycles, and include the legal foundation for dealing with loss and damage from climate change. The two negotiating groupings called for the Paris protocol to be designed to rapidly increase mitigation ambition, including for 2025 and 2030, so as to increase emission reduction action to achieving this crucial temperature goal.

The Climate Vulnerable Forum is a South-South cooperation platform for 20 participating governments to act together on climate change. The CVF has issued the Manila Communique, calling for an evidence-based strengthening of the climate goal at COP21 to 1.5°C. On the first day of the Paris climate summit COP21, leaders of 30 countries most vulnerable to climate change jointly issued a historic Manila-Paris Declaration which calls for full decarbonisation of the world economy, 100% renewable energy by 2050, and zero emissions by mid-century in order to keep the world on track for below 1.5°C degrees of warming.

Awareness campaigns

#1o5C


A campaign launched by the Climate Vulnerable Forum and CARE, calling for strengthening the long term temperature goal to 1.5°C.


#1point5toStayAlive


Caribbean climate justice initiative launched ahead of the Paris climate summit by Panos Caribbean, the Government of Saint Lucia and Caribbean Community Climate Change Centre. The website is a source of news, resources, information on actions you can join, films and music for climate justice by Caribbean artists.


External resources:

The report of the Structured Expert Dialogue

This link will take you to the full report of the Structured Expert Dialogue (SED).

10 Key Messages from the Structured Expert Dialogue

Short summary of the 10 key messages from the final report of the SED

Turn Down the Heat – Climate Extremes, Regional Impacts and the Case for Resilience

This link takes you to the World Bank´s report on climate impacts in Sub-Saharan Africa, South Asia and South-East Asia. Each regional chapter provides a table comparing impacts at 1.5°C, 2°C and 4°C warming.

Turn Down the Heat – Confronting the New Climate Normal

This link takes you to the World Bank´s report on climate impacts in Latin America and the Caribbean, Middle East and North Africa and Europe and Central Asia. Each regional chapter provides a table comparing impacts at 1.5°C, 2°C and 4°C warming.

What will it take to limit warming below 1.5°C?

Feasibility of limiting warming to below 1.5°C

This page outlines the scientific, technical and economic feasibility of holding warming well below 2°C, and below 1.5°C by 2100. It addresses the consequences of limited climate action to date, it discusses implications for the negotiations on a new climate agreement in Paris, and it reviews some critical mitigation options, like decarbonisation, renewables, bio-energy, carbon capture and storage, and the combination of the latter two – BECCS.

Technical background in Feasibility of limiting warming to 1.5°C and 2°C

This briefing note outlines the scientific conditions under which warming can be limited to well below 2°C over the 21st century, and return to below 1.5°C by 2100. It provides a scientific overview of the science on some critical mitigation technologies, like bioenergy, carbon capture and storage, and their combination – BECCS. It also contains counter arguments to claims that 1.5°C scenarios undermine food security through including large scale bioenergy deployment. The considerations in this briefing are based on the findings of the Fifth Assessment Report of the Intergovernmental Panel on Climate Change (IPCC AR5), the 2014 UNEP Emissions Gap Report, the Report of the UNFCCC Structured Expert Dialogue (SED), as well as the recent scientific literature.

1.5°C risks and feasibility – key points

This fact sheet provides key points on risks to ecosystems, food security and sustainable development associated with 1.5°C warming. It also provides responses to arguments commonly made against 1.5°C and provides the scientific evidence for each point made.

Is it possible to return warming to below 1.5˚C within this century?

This briefing comments on the feasibility of holding warming below 1.5°C within this century and provides information on selected climate risks at 1.5°C, 2°C and 4°C warming.

The CAT emissions gap – How close are INDCs to 2 and 1.5°C pathways?

This page on the Climate Action Tracker (CAT) website shows the levels of warming associated with submitted INDCs and provides an assessment of the resulting gap to meet the 1.5°C or 2°C goal.

What do the CAT, UNFCCC Synthesis Report and the UNEP 2015 Emissions Gap report say about the prospects of limiting warming to below 2°C and 1.5°C from INDC levels for 2025 and 2030?

This page on the Climate Action Tracker (CAT) website shows the levels of warming associated with submitted INDCs and provides an assessment of the resulting gap to meet the 1.5°C or 2°C goal.

Report The ten most important short-term steps to limit warming to 1.5°C

This Climate Action Tracker report spells out ten important, short-term steps that key sectors – including energy generation, road transport, buildings, industry, forestry and land use, and commercial agriculture – need to take to help the world achieve the Paris Agreement’s 1.5°C limit.
The summary of the report is available here.

Report Implications of the Paris Agreement for Coal Use in the Power Sector

This report looks into the implications of the Paris Agreement for coal fired electric generation. It shows that the Paris Agreement 1.5°C temperature limit requires a quick phase-out of coal used for electric power generation.

What does the Paris Agreement mean for Finland and the European Union?

This report commissioned by a Finnish public fund Sitra looks at the implications of the 1.5°C limit in the Paris Agreement on energy and climate policy in Finland and the European Union. The report is in English and contains a summary in Finnish.

Implications of the 1.5°C limit in the Paris Agreement for climate policy and decarbonisation

This report, commissioned by the Climate Institute in Australia, examines the impacts on Australia of limiting global temperature rise to 1.5°C and 2°C, and to provide estimates of the global carbon budgets associated with achieving these temperature limits.

Differences between carbon budget estimates unraveled

This peer-reviewed article assesses the differences between various carbon budget estimates from IPCC and other sources, and identifies the most appropriate carbon budget for holding warming below 2°C.



External resources:

What would it take to limit climate change to 1.5°C?

This link will take you to the press release of the International Institute for Applied Systems Analysis´ (IIASA) on the publication “Energy system transformations for limiting end-of-century warming to below 1.5°C” by Rogelj et al. in Nature Climate Change.

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