International Climate Assessments – Round Six

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The Intergovernmental Panel on Climate Change (IPCC) has recently published the third and final part of its review of global climate research. Known as Assessment Report Six (AR6), it is the first comprehensive review since 2013.

At nearly 3000 pages, and with the summary for policy makers amounting to over 60 pages, it has been criticised for being inaccessible – this blog provides a summary of the key points.

What’s in Part One and Part Two of AR6?

Part One of AR6 was published in August 2021 and set out the physical science (explored in more detail in a SPICe Blog on the Science Behind COP26). It noted that, at the current greenhouse gas emissions trajectory, the world is set to pass 1.5°C warming (the legally binding goal set by the Paris Agreement) by 2040.

Part Two of AR6 was published in February 2022 and explored the impacts on people and nature, and how to adapt. Some key points:

  • Half of the global population is already vulnerable to water insecurity and billions more are at risk of extreme heat, flooding, and hunger.
  • It was unequivocal that some climate impacts and losses are irreversible including terrestrial, freshwater and coastal/marine ecosystems. These ecosystems are also human life support systems.
  • Proven ways to adapt, include improving food and water security and preserving nature, but projects are not fairly distributed, are chronically underfunded, short-term and do not create “transformational” change.
  • Not everyone is affected equally, and the poorest and most marginalised communities will be hardest hit. Therefore, every 0.1°C of warming matters because the magnitude and rate of impacts “escalate with every increment of warming”.

Part three of AR6

The science behind Parts One and Two is well known and has been part of established scientific discourse for many years. Similarly, Part Three of AR6 doesn’t contain any big surprises, but it does update a globally common reference point for political action and policymaking.

The good news

IPCC Chair, Hoesung Lee stated:

I am encouraged by climate action being taken in many countries. There are policies, regulations and market instruments that are proving effective.  If these are scaled up and applied more widely and equitably, they can support deep emissions reductions and stimulate innovation.

AR6 shows from 2010-2019 average annual global emissions were at their highest levels in human history, but the rate of growth has slowed from an annual average of 2.1% at turn of century to 1.3% between 2010 – 2019.

Since 2010, there have been sustained decreases in the costs of solar and wind energy, and batteries (up to 85%). An increasing range of policies and laws have enhanced energy efficiency, reduced rates of deforestation and accelerated the deployment of renewable energy.

If an emissions reduction pathway of 1.5°C was adopted, it is forecast that global GDP in 2050 would be around 2.5 – 4.2% lower than “business as usual” scenarios, put another way by Professor Michael Grubb, a lead author:

If you take the most aggressive [mitigation] scenarios in the entire report, it would cost, at most 0.1% of the rate of annual GDP growth assumed.

These estimates do not consider the economic benefits of avoiding climate change and the lowering cost of adaptation measures, nor do they put a price on co-benefits such as cleaner air and water. This has been described as “viable and financially sound” by UN Secretary General Antonio Guterres.

The bad news

In short, without immediate and deep emissions reductions across all sectors, limiting global warming to 1.5°C is considered to be beyond reach.

To achieve this, global emissions would have to peak before 2025 and reduce by 43% by 2030. Even if this is achieved, “it is almost inevitable that we will temporarily exceed this temperature threshold but could return to below it by the end of the century”. Known as overshoot scenarios, temporarily exceeding temperature goals significantly increases the risk of irreversible ecosystem damage.

Based on current emissions, the world is on track for warming of 3.2°C by the end of this century – more than double the limit agreed in the Paris Agreement. Antonio Guterres has strongly condemned the inaction:

Some government and business leaders are saying one thing – but doing another. Simply put, they are lying. And the results will be catastrophic.

AR6 makes it clear that whilst individual behaviour changes and adopting greener lifestyles can help (explored below), sweeping structural and cultural change is also needed. Professor Jan Christoph Minx, one of the lead authors stated:

[…] the big message coming from here is we need to end the age of fossil fuel. And we don’t only need to end it, but we need to end it very quickly.

The scale of the challenge

IPCC Chair Hoesung Lee stated:

We are at a crossroads. The decisions we make now can secure a liveable future. We have the tools and know-how required to limit warming.

However, the scale of the challenge is colossal. AR6 sets out that for temperature rises to be kept within 1.5°C, global coal use needs to drop by 95%, oil use by 60% and gas by 45% by 2050. This comes at a time when high inflation and international conflict mean that fossil fuel prices are rising, and governments around the world are thinking about increasing production from existing sources, and speeding up the exploration and exploitation of new ones. Indeed, the UK Government’s new Energy Security Strategy has undertaken to launch another oil and gas offshore licensing round, and to commission an “impartial technical review” of onshore gas (commonly known as fracking).

AR6 is clear that fossil fuels will have to be replaced with “widespread electrification, improved energy efficiency, and use of alternative fuels (such as hydrogen)”.

For the first time, the IPCC report explores behavioural and cultural changes which are considered to represent significantly “untapped potential”, and AR6 is clear of the need for:

Systemic infrastructure changes that enable behavioural modifications and reductions in demand […].

Having the right policies, infrastructure and technology in place to enable changes to lifestyles and behaviour could result in a 40 – 70% reduction in emissions by 2050 and can improve health and wellbeing. In practice this means targeting and reducing emissions from what we eat, how we deal with food waste, and how we travel, particularly in urban areas.

What is Scotland doing about it?

Prior to hosting COP26, Scotland’s Climate Change Plan, and progress in reducing economy wide emissions were the subject of joint scrutiny by four Parliamentary committees, whose conclusions were largely the same as those of statutory advisers the Climate Change Committee, and the IPCC.

These solutions are well known and have been part of established scientific and policy discourse for many years – energy efficiency, demand reduction, new technologies, and structural change to support low carbon behaviour. In short, bigger, better, faster, more …

A new Climate Change Plan is currently being developed by the Scottish Government, to take into account the unanimously agreed target of net-zero emissions by 2045.

The most recent statistics show that Scotland has failed to achieve its annual emissions reduction target in each of the last three years. Figures for 2019 show that emissions fell 51.5% against the baseline, well short of the 55% target.

Science vs diplomacy

International climate science isn’t the same as international climate diplomacy, and the science is settled. As a recent editorial in the Financial Times points out:

The science of climate change is now well understood, as are the technical solutions. The larger problem is politics, as the IPCC itself showed. Its report was held up by wrangling among the 195 countries approving it, some of which depend heavily on fossil fuels or the lack of resources to build a greener economy. After more than a century of unsustainable energy and land use, the world has begun to turn. New ways of shifting even faster must now be found.

Alasdair Reid, Senior Researcher – Energy, Climate Change and Land Reform