It’s been a bad couple of weeks for the world’s climate and environment. The inauguration of billionaire property developer and reality TV star Donald Trump as the 45th President of the United States has presaged a new Dark Age of climate politics.

In an opening fortnight of controversial executive orders, President Trump has decreed the expansion of major fossil fuel developments including the controversial Keystone XL and Dakota Access oil pipelines, and the neutering of long-standing environmental protections. In addition, he and his leadership team have made it plain they intend to dismantle many of the Obama administration’s climate initiatives and withdraw from the Paris Climate Agreement. All this runs in direct counterpoint to the rapid decarbonisation required to avoid dangerous climate change.

For Australian fossil fuel interests, President Trump’s war on climate appears particularly opportune. Just last week, Prime Minister Malcolm Turnbull and his senior ministers floated the idea of government backing for new coal-fired power stations as part of the government’s response to Australia’s “energy security” and expressed reticence over the country’s Renewable Energy Target.

For a country that has nurtured world-leading innovations in solar photovoltaic and other renewable energy technologies and that is particularly vulnerable to the effects of climate change – be it in the form of record heat, devastating floods, more widespread drought, coastal inundation from sea level rise combined with stronger tropical storms, or the demise of the Great Barrier Reef – doubling down on the traditional fossil fuel energy path is particularly short-sighted.

Of course this hostility to climate action and the decarbonisation of our economies is not new. The attacks on climate action by the Trump presidency and the Turnbull government’s embrace of the discourse of “clean coal” reflect the toxic, partisan political war that has engulfed US and Australian climate policy over several decades. Sound policy has been held hostage by the same vested interests of a large and powerful fossil fuel sector and a traditional vision that jobs and economic growth can only come from the “extractivism” that has defined 19th and 20th century economics.

Indeed, since the widespread scientific acknowledgement of human-caused climate change in the late 1980s and early 90s, we have witnessed the development of a highly sophisticated and influential climate change denial industry. Consisting of major fossil fuel corporations, industry groups, lobbyists, “free-enterprise” think-tanks and conservative politicians, this counter-movement has proven remarkably successful in delaying the political actions necessary to curtail greenhouse gas emissions.

Like big tobacco before them, fossil fuel advocates have attacked mainstream climate science to confuse the public and policymakers about the reality and threat of human-caused climate change. As a result, we have seen a full-scale assault on a century and half of established science. For many climate scientists this has involved attacks from conservative politicians and rightwing lobby groups, orchestrated campaigns of harassment via mainstream and social media, challenges to job security and careers, and in some cases, death threats. Indeed, as recounted in The Hockey Stick and the Climate Wars, one of us (Michael Mann) has been subject to all of those things.

Beyond destroying our politics and corroding public trust in science, climate change denial also threatens the future of a habitable planet and a viable global economy. As a growing body of research has revealed, the maintenance of a “fossil fuels forever” mentality has real implications for the future of global food production, biodiversity, social functioning and geopolitical security. Leading economies around the world have recognised that the decarbonisation of energy and transport systems are key to the future prosperity of human civilisation.

The dramatic fall in the cost of renewable energies and commitment to large-scale investment in solar and wind energy highlight a pathway away from coal, oil and gas. But government leadership is badly needed to take the threat of climate change seriously and ramp up the scale of economic transformation on a par with the political and economic mobilisation we have applied to other existential threats in the past.

The good news is that there is still time to prevent the worst climate changes from occurring. The Paris climate agreement was a step forward in that the nations of the world committed to reductions that get us half way from where we would otherwise be headed (more than 5C warming of the planet relative to pre-industrial temperatures by the end of the century) and to where we need to be (stabilisation of warming below 2C or so). The Paris agreement moved us on to a pathway where, with additional ratcheting up of commitments, we can limit warming below truly dangerous levels. That doesn’t mean it will be easy, but there is still a path forward.

In the US and Australia, we must shift away from a culture of politically motivated climate change denialism to an acceptance of the truly existential threat now facing humanity. We are in grave need of courageous political leadership and a rejection of vested interests engaged in bad faith efforts to delay the needed transition away from fossil fuels toward renewable energy. To do otherwise, ensures an increasingly grim future for our children, humanity and the planet.