I was sent a link to this statement by the Pontifical Academy of Sciences on the subject of climate change. It's gloriously over the top, as you would expect from something authored by Schellnhuber and Sachs, among others.
This century is on course to witness unprecedented environmental changes. In particular, the projected climate changes or, more appropriately, climate disruptions, when coupled with ongoing massive species extinctions and the destruction of ecosystems, will doubtless leave their indelible marks on both humanity and nature. As early as 2100, there will be a non-negligible probability of irreversible and catastrophic climate impacts that may last over thousands of years, raising the existential question of whether civilization as we know it can be extended beyond this century. Only a radical change in our attitude towards Creation and towards our fellow humans, complemented by transformative technological innovations, could reverse the dangerous trends that have already been set into motion inadvertently. A sustainable future based on the continued extraction of coal, oil and gas and their use in the “business-as-usual mode” will not be possible, because it raises the specter of a world that could be significantly warmer than 2°C by the end of this century. Such a temperature rise, occurring in a warm inter-glacial epoch that we call the Holocene, has not been seen in tens of millions of years. This creates a serious risk that Earth will cross critical thresholds and tipping points, pushing whole environmental systems, such as rain forests, continental ice sheets, coastal wetlands, monsoon patterns and marine food webs into different states or even annihilation. To quote the most recent IPCC (Intergovernmental Panel on Climate Change) Synthesis Report released in 2014: We risk “increasing the likelihood of severe, pervasive and irreversible impacts for people and ecosystems.”
One hardly knows where to start, but it's worth taking a look at what AR5 had to say about "tipping points". Here's Table 12.4, which was covered in this BH guest post about a Royal Society discussion meeting at which it was discussed. As my correspondent put it at the time,
Every single catastrophic scenario bar one has a rating of "Very unlikely" or "Exceptionally unlikely" and/or has "low confidence".
;)
Still, for greens and their fellow travellers, this is probably good enough to justify depriving Africans of the benefits of fossil fuels.