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What's the difference between a +1.5°C and a +4°C World?

*In 1880 – the average temperature of planet Earth was 13.7°C

*In 1990 – it was 14.3°C

*In 2019 it was 14.9°Cⁱ

That means in the past 200 years we have increased the average temperature by up to 1.2-1.3°Cⁱⁱ. In 2015 world leaders vowed to hold global temperature rise at 1.5°C.

More critically, based on current projections of greenhouse gas (GHG) emissions, the average temperature of the Earth will increase by 4°C before the end of the centuryⁱⁱⁱ.

The ramifications of a hotter world and the shift from a 1.5°C to a 4°C temperature increase are profound and will change every aspect of society as these scenarios show.


The picture above is stark but it is not too late to avoid the worst. We live in a world in which scientists now know, with great accuracy, how different levels of GHG emissions lead to different temperature outcomes.

While there is always some uncertainty, there is no big mystery and no room for excuses. There can be no looking back and saying, ‘we didn’t know’. We can still save ourselves and our planet, but we must make an explicit choice to do so, and quickly (Lynas 2020).

To meet the 1.5°C target we need to cut our global GHG emissions in half within a decade and achieve net zero by 2050ˣ. Yet GHG emissions continue to be record-setting highs every year. Even if we manage to achieve this temperature increase the global consequences of breaching our planetary limit will be profound.

We call on businesses and government to commit to measure our full impact on the planet’s resources and to base reduction targets on what the world needs them to do.

Article 13 helps organisations to assess their real impact on what the world needs to survive. We recently reviewed the sustainability targets 240 of the world’s largest companies, see a snapshot of our research findings here







[vi] Mark Lynas Our Final Warning Degrees Emergency





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