Whatever combination of forces led to Donald Trump becoming President of the United States - and for at least the next 4 years, control of nearly a quarter of the global economy, with his finger on the nuclear button - remains a frightening mystery to most of us. Now he has that control and is showing his disruptive leadership style he would do well to remember Newton’s third law “To every action there is an equal and opposite reaction”.

Already many of his Executive Order initiatives have begun to demonstrate this reality - starting with his initial quasi ban on Muslims from 7 countries and the instant, outrage, demonstrations, and court challenges. Or his “Day One - Repeal Obamacare” followed by the realization that you can’t without a replacement and that needs Congress to build as well as knock down. His “Great Wall of Mexico” and Fix Sanctuary Cities mantra – both producing predictable defiance and deepening opposition. And on and on….

And you can’t play reality TV games by threatening to unilaterally impose tariffs or border taxes in a fit of pique and overturn delicate trade arrangements crafted to bring balanced benefits to all parties. You do so at the peril of retaliation and adding hidden costs to US consumers. Yes it would be putting America first for Apple to build i-phones entirely in the USA – it would just make them prohibitively expensive, reduce sales massively and put Chinese factories out of work. So, what then if China, already stung by currency accusations, and threats to its one China policy, decides to encourage its travellers to shun the USA. Chinese tourists are an important US export - the negative impact would pretty soon hit the US economy “bigly.”

Donald Trump is a man who is inclined to toss out an outrageous idea, “double-down” on his positions while offering a glimmer of hope that he’ll change his mind, based on his “Art of the Deal” tactics. What he doesn’t seem to get is that you can’t bully or play legal games with sovereign state partners for long, the way you did as a businessman with small companies, a pseudo university, and loopholes in the tax code. Or unravel decades of partnership obligations with a smart one liner, the stroke of a pen and a barrage of 140 character tweets.

Most importantly, Donald Trump would also do well to remember there is a real elephant in the room - climate change - that it’s existential and it doesn’t have a twitter account. He has already signalled his disdain for the Paris Treaty and placed shackles on the Environment Protection Agency in his first week in office, in addition to nominating a climate change sceptic as Administrator. And at the same time opening dormant pipelines and pledging to give big oil a new state supported lease of drilling life.

All this, while the science and the experts make it clear that Sandy type storms, Louisiana type floods, Kansas type tornados and California style droughts will only get more intense, more frequent and more costly. And it will hit everyone, everywhere - inside the US and with similar patterns around the world.

These realities won’t change because Donald Trump threatens to tear up the one deal that every country on earth supports as the best chance for a survivable future. It’s time to “walk-back” the thoughtless anti-Paris rhetoric and get on board with the rest of humanity.

Professor Geoffrey Lipman SUN