It is a frightening thought that that our current global warming situation could have been much worse.

It is doubly frightening when we consider that’s only the case because of an international agreement which Australia back then, unlike its current attitude to climate change agreements,  embraced.

In 1987 most of the world signed the Montreal protocol which controlled the use of synthetic chlorofluorocarbons (CFCs) which had opened up holes in the ozone layer. A key driver of the Protocol was President George H. Bush back in the days when Republican Presidents could be both green and rational.

In a Nature Climate Change article (18 August 2021) Niklas Boers of the Lancaster University Environment Centre said “The control of the production of ozone-depleting substances through the Montreal Protocol means that the stratospheric ozone layer is recovering and that consequent increases in harmful surface ultraviolet radiation are being avoided. The Montreal Protocol has co-benefits for climate change mitigation because ozone-depleting substances are potent greenhouse gases.”

Boers’ what the ‘world-avoided’ research shows that the international co-operation has two benefits. First, it increased the Earth’s carbon sink and it is estimated that there “could have been 325–690 billion tonnes less carbon held in plants and soils by the end of this century (2080–2099) without the Montreal Protocol.” Second, that without the change there could have been “an additional 115–235 parts per million of atmospheric carbon dioxide, which might have led to additional warming of global-mean surface temperature by 0.50–1.0 degrees”

However, in Australia we have to temper the good news with our current political reality. The latest IPCC report points out that methane is second only to carbon dioxide in its contribution to global warming. It’s followed by nitrous oxide and hydrogenated gases.

Scott Morrison is busy promoting – along with his oil and gas proponents and donors – the role of methane in energy production. If Australia handles it as well as it’s handled the pandemic and climate change the situation might be worse than the IPCC predicts.

Cutting back industry and agricultural methane production should also be a high priority. Obviously changing the feed of Australia’s farm animals would partly tackle that problem but then who knows whether that would be enough to counteract the effects of the odd Barnaby Joyce rhetorical explosion.

The Economist (11 August 2021) introduced its analysis of the IPCC report by saying: “At a key moment in the film Jaws, police chief Martin Brody, having known that a shark attack was possible, witnesses one actually happen. The director, Steven Spielberg, underlines the transformative nature of Brody’s shock with a shot which makes inspired use of a camera technique called a dolly zoom. Nothing on screen actually moves. But Brody’s guilty face seems to rush towards the audience, taking up more and more of the frame. At the same time his surroundings, rather than being displaced, are revealed more fully.”

It is the point when Brody “realises that the opportunity to avert calamity is gone; his inaction has led to a covert threat becoming a blood-in-the-water reality.” Needless to say this leads to conflict between police chief and mayor with the mayor wanting to downplay it all to avoid scaring off the tourists.

Meanwhile another major climate problem is emerging. One that makes the bottle of the English Hattingley Valley bubbly Boris Johnson recently gave Scott Morrison very valuable in the years ahead when, hopefully, he is no longer damaging Australia and unable to resist serious action on climate change.

Due to climate change the south east of England is now producing a wide range of high quality sparkling wines. French producers are buying land and establishing vineyards there as rising temperatures are causing problems in some champagne growing areas and Jancis Robinson, among others, has been praising the quality of the English production.

That good fortune may not last as more evidence is emerging that the Gulf Stream, the Atlantic Meridional Overturning Circulation (AMOC), the key circulation system of the Atlantic Ocean, transporting warm masses northward from the tropics at the surface and southward at the bottom of the ocean from near Greenland may be breaking down.

A number of scientists undertook research last year, published in a March 2021 PNAS paper, which said: “the recently discovered AMOC decline during the last decades is not just a fluctuation related to low-frequency climate variability or a linear response to increasing temperatures. Rather, the presented findings suggest that this decline may be associated with an almost complete loss of stability of the AMOC over the course of the last century, and that the AMOC could be close to a critical transition to its weak circulation mode.”

A Nature geoscience paper, Current Atlantic Meridional Overturning Circulation weakest in last millennium, published in February this year firmed up the conclusions.

The authors compared a variety of published proxy records to reconstruct the evolution of the AMOC since about 400CE. The flow has only been directly measured since 2004 and these proxy measures provide significant additional data.

What will Scott Morrison do about all this? Our promises, promises never delivering ever diverting PM has form on these issues.

In 2019 he told a plastic industry conference: “We need to take action on climate change but there are actually issues like plastics which prevent even more immediate threats.” In 2020 he proposed new rules and regulations on recycled plastic targets.

Needless to say he has never delivered them.

The Nature and PNAS papers were brought to the author’s attention by John Spitzer.