
Following the Europe-wide launch of the IPCC Special Report on Global Warming of 1.5°C at Imperial, chapter lead-authors Professor Myles Allen from the University of Oxford and Imperial’s Dr Joeri Rogelj, gave their personal take on the report at a joint event between Grantham Institute and the Royal Meteorological Society. So, what did we take away from this conversation about how to avoid the worst effects of climate change? The Grantham Institute’s Simon Levey and science communicator Claudia Cannon summarise:
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There are real and identifiable differences between the effects of global warming at 2°C and 1.5°C
Much of the scientific community was as surprised as the rest of us to see laid bare the real and identifiable difference in the effects of global warming at 2°C and 1.5°C above pre-industrial levels. This striking infographic depicting the findings of the IPCC’s report by the World Resources Institute shows the scale of climate change impacts on global factors like extreme heat (2.6 times worse), lost crop yields (2.3 times worse), species extinctions (2-3 times worse) and coral reef loss. On this last point, the report suggests that 2°C climate change will mean 99% of all coral reefs are lost.

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It’s not all about giving up stuff we like
One audience member asked how ordinary citizens might respond to questions about their excessive ‘consumption’ and making potentially unappealing lifestyle changes. Dr Rogelj’s response? “Depending on which strategy you follow… it’s not necessary to have a reduction in energy consumption – we just need to harness that energy in smarter, more energy efficient ways.” However, this is no Get Out of Jail Free card, since the report also shows how the consequences of these decisions (or lack of action) might negatively affect sustainable development in other areas.
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The ‘costs’ are not quite what they seem
Professor Allen says he often hears conversations framed around ‘what it will cost’ to make the changes that will improve our planet for the better. For example, he says, you could think that limiting warming to 1.5°C would ‘cost’ 2.8% of global GDP [Gross Domestic Product] between now and 2050 to make the energy system low-carbon and sustainable. However, firstly, this figure would be more accurately portrayed as an investment rather than a cost. Plus, it fails to recognise that about 2% of GDP is already invested annually in energy infrastructure, including fossil fuel energy. “So yes, it’s more money, but clearly for a very different outcome,” Professor Allen says.
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Climate change is just one of several linked global problems
Not wishing to do climate scientists out of a job, Dr Rogelj says, “we should not be focusing solely on this one objective, [climate change]”. The report shows that avoiding the worst effects of climate change goes together with all the United Nations Sustainable Development Goals (below) to improve peoples’ lives across the world. There are possible trade-offs and they will have to be carefully managed. However, the benefits and advances that come with sustainable development will only be possible for all nations and people if climate change and other problems are tackled together.
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But everyone really wants to find a solution
The IPCC lists almost 50 reports on their website, full of scientific and technical information. A seasoned IPCC author, Professor Allen says he was impressed by how far everyone’s perspectives have evolved in recent years, and the willingness of governments to consider implications such as ethics and equity. Collaboration between countries and their governments was “remarkable”, he explained. “This process itself is a kind of example of the cooperation we need.”

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Scientists have given us the data, now it’s time to get on with the job
In 2015, the Paris Agreement saw 197 governments get together to say ‘we want to keep global warming below 2 °C, or preferably 1.5 °C’. For this report, scientists were asked, ‘What are the implications if we want to limit warming to 1.5°C?’ … and, ‘What is the difference in impacts between 1.5°C and 2°C?’. “We provided an answer,” Dr Rogelj says. “And what policymakers decide to do with that information is no longer in our hands.”
Read more
Watch a film of the event on the Grantham Institute’s YouTube Channel
Reactions to the Special Report from Imperial experts
Green GB Week events at Imperial
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