“Everything must change,” says Tancredi Falconeri in Giuseppe Tomasi di Lampedusa’s novel The Leopard, “in order that everything can remain the same.” And what was true for the Sicilian aristocracy at the time of the unification of Italy is still true in today’s tumultuous world: If the old order wants to maintain its position at a time of great societal upheaval, it can do so only by co-opting the language of radical change. Donald Trump gets this, and so do the billionaire Barclay brothers who, from their Lampedusian perch on the Isle of Sark, have been bankrolling the false populism of the Brexit campaign.

But I am not here to attack the lies and cynical strategies of these pseudo-populists. They will expose themselves soon enough now that they are in power and can no longer inveigh against the ruling elites. What interests me more is whether my own people within the world of environmentalism and impact investing are guilty of a similar false logic. Are we not also latter-day Tancredis in our insistence that if we change everything about the composition of the world’s energy supply, then everything else can remain the same? If our cars are electric, we can buy as many as we like; if our electricity is renewable, we can crank up the air conditioning, and if our planes run on biofuel, we can jet to Dubai for a weekend of indoor skiing.

Now don’t get me wrong: Electric cars, renewable energy, and biofuels are good things. But unless we simultaneously and significantly reduce our energy use and our consumption of raw materials, all the good alternatives in the world will still see us hurtling toward extinction. The notion that we can carry on exactly as before so long as we go renewable is, to flip Al Gore’s phrase on its head, “a convenient lie.”

And worse than being a lie, the notion is itself contributing to locking in irreversible climate change. Almost everything we construct or consume today requires fossil fuels. Reading this article has a carbon footprint, and so does building a solar panel or a wind turbine. Sure, once installed, a renewable installation will have a far lower footprint than an equivalent fossil fuel installation, and over time it will repay its original debt. But there is no guarantee that it will replace a fossil fuel installation; without a reduction in demand, the two structures might carry on in tandem. This is precisely what is happening at the moment: The proportion of renewables in the global energy mix is constantly increasing, but so too is the total amount of energy being produced. We are not replacing fossil fuels with renewables; we are just adding them on top.

Looking further down the line, one could hope that as older power plants are decommissioned the carbon intensity of our energy generation will start to drop. But this is a very long game to play and is not appropriate to the time-sensitive context in which we find ourselves.

So how can we bring about genuine change? First, we in the developed world simply need to consume a lot less energy. We can achieve this reduction partly by personal effort, but as sociologist Zygmunt Bauman points out in his book Liquid Modernity one of the perversities of modern societies is that in return for giving citizens a superficial form of freedom, they expect citizens to take responsibility for decisions far beyond their control. The only way we can reduce energy consumption at the scale necessary is via policy and regulation. To use an example from France, where I live: We cannot ask drivers to tackle toxic levels of air pollution in major cities by leaving their cars at home while simultaneously using the number of cars Renault sells each year as an indicator of the nation’s economic performance. A coherent policy approach to climate change would involve increased investment in public transport and would no longer use car sales as a tool for calculating gross domestic product.

Second, the global community needs to set a timeline for phasing out fossil fuel use and, in the 20 years left before we overshoot the two degrees Celsius upper limit of the Paris agreement, redirect a proportion of existing fossil fuel combustion toward the construction of renewable energy infrastructure. And bear in mind that redirecting toward one thing means redirecting away from something else; a wise use of our remaining carbon budget over the next two decades will require a certain amount of government intervention, in a manner analogous to the requisitioning of industry that went on during World War II. It will also—and we should not duck the issue—involve a certain amount of sacrifice and hardship. Reducing our overall energy consumption while simultaneously building a new renewable infrastructure will mean that there is less energy available for certain activities we currently take for granted: The lights might not always go on when we flick the switch.

Third, private and public sector actors will need to engage on a huge program of tree-planting to absorb excess carbon in the atmosphere, rebuild degraded ecosystems, and take the stress off our oceans, which are currently acting as a carbon sink. The sheer number of trees that we will need to plant to make a positive impact will necessitate a mixed approach combining reforestation, forest conservation, and sustainable management of plantation timber. The restoration of degraded farmland also holds potential as a tool for sequestering atmospheric carbon.

And finally, all these measures will need to be undertaken in a way that is compatible with continued economic improvement for the poorest members of society. We have a moral duty to ensure that our efforts to combat climate change do not come at the expense of today’s poor. Reducing poverty will also help reduce the rate of population growth, another vital step toward a genuinely sustainable society that offers equal opportunity to all.

These are colossal challenges, but given the very high stakes—the survival of our species—politicians and public figures have nothing to lose in speaking openly about these matters. If there is one positive lesson to be learned from recent events in Britain and the United States, it is that the public reacts favorably when it feels people are speaking honestly. The answer to climate change is about more than electric cars and renewable energy; we have an obligation not just to speak frankly, but also—and unlike Trump and the Brexiteers—to tell the truth.