This article from The Conversation clarifies what the 12 year warning issued by the IPCC actually means because it is widely misundestood.
My biggest concern is with the much-touted line that “the Intergovernmental Panel on Climate Change (IPCC) says we have 12 years” before triggering an irreversible slide into climate chaos. Slogan writers are vague on whether they mean climate chaos will happen after 12 years, or if we have 12 years to avert it. But both are misleading.
As the relevant lead author of the IPCC Special Report on Global Warming of 1.5°C, I spent several days last October, literally under a spotlight, explaining to delegates of the world’s governments what we could, and could not, say about how close we are to that level of warming.
Using the World Meteorological Organisation’s definition of global average surface temperature, and the late 19th century to represent its pre-industrial level (yes, all these definitions matter), we just passed 1°C and are warming at more than 0.2°C per decade, which would take us to 1.5°C around 2040.
That said, these are only best estimates. We might already be at 1.2°C, and warming at 0.25°C per decade – well within the range of uncertainty. That would indeed get us to 1.5°C by 2030: 12 years from 2018. But an additional quarter of a degree of warming, more-or-less what has happened since the 1990s, is not going to feel like Armageddon to the vast majority of today’s striking teenagers (the striving taxpayers of 2030). And what will they think then? ….
Climate change is not so much an emergency as a festering injustice. Your ancestors did not end slavery by declaring an emergency and dreaming up artificial boundaries on “tolerable” slave numbers. They called it out for what it was: a spectacularly profitable industry, the basis of much prosperity at the time, founded on a fundamental injustice. It’s time to do the same on climate change.
Creating a zero-emission society in the UK has become a major cause and it will receive further serious promotion next week when the government’s climate change committee publishes its report on how, and when, Britain can achieve this status and play a proper part in the battle against global warming. Another scientist on staying below 1.5C global target by reducing carbon emissions (Observer article 21.01.19)
Slow burn? The long road to a zero-emissions UK Extinction Rebellion protesters want a carbon-free UK by 2025. But can the financial and political hurdles be overcome?
“If the world limits emissions of carbon dioxide to no more than 420 billion tonnes this century, we will have a two in three chance of keeping global warming down to around 1.5C.
“However, if we go above to 580 billion tonnes then our chances will be reduced to 50-50. The problem is that in 2017 alone, a total of 42 billion tonnes of carbon dioxide was emitted in a single year. By that calculation, we clearly do not have a lot of time to waste.”