On August 18, 2025, the world found itself at a crossroads—one defined by the stark realities of climate science and the persistent ambitions of the fossil fuel industry. A pair of recent reports, one from climate scientists and another featuring the chief executive of Chevron, have set the stage for a heated debate about the future of energy, the pace of emissions cuts, and the very viability of keeping global warming within safe limits.
According to Live Science, more than 60 leading climate scientists warned that the remaining “carbon budget” to keep global temperatures below the critical 1.5°C warming threshold could be depleted in as little as three years if emissions continue at their current rate. The planet’s carbon budget—the total amount of carbon dioxide humanity can emit before surpassing this pivotal mark—now stands at just 143 billion tons (130 billion metric tons). With annual emissions currently at about 46 billion tons (42 billion metric tons), the math is sobering. The world is already 1.2°C warmer than preindustrial levels, and nearly all of this increase is attributable to human activity.
But what happens if we overshoot? Is climate catastrophe inevitable, or is there still hope for reversal? The answer, it turns out, is complex. "Every fraction of a degree of warming that we prevent makes us better off," Michael Mann, director of the Center for Science, Sustainability and the Media at the University of Pennsylvania, told Live Science. Mann’s perspective is echoed by many in the scientific community: while passing the 1.5°C threshold would raise the risk of irreversible ecosystem changes—especially for island nations and vulnerable regions—it does not spell instant apocalypse. Yet, the urgency to act could not be clearer.
The situation is further complicated by the delayed response of the climate system. Even if humanity were to cut carbon emissions to zero overnight, global temperatures would continue to rise for several decades. This is because the oceans, which have absorbed much of the excess heat generated by greenhouse gases, will gradually release that heat back into the atmosphere. The National Oceanic and Atmospheric Administration (NOAA) estimates that this process alone could add another 0.5°C of warming before temperatures stabilize—and that’s if emissions stop entirely today. Over thousands of years, natural carbon sinks like forests and soils would eventually draw down atmospheric CO2, but for now, the world faces a lag between action and effect.
Why is 1.5°C such a crucial threshold? Kirsten Zickfeld, professor of climate science at Simon Fraser University, explained to Live Science that this figure represents the upper limit of what the global climate system can withstand while still allowing societies to “manage the consequences.” Beyond 1.5°C, the risks of triggering so-called climate tipping points—such as the collapse of the Greenland Ice Sheet or the conversion of the Amazon rainforest into a savanna—rise dramatically. These tipping points could lock in changes that are, for all practical purposes, irreversible on human timescales.
The challenge of reversing temperature rise once the threshold is crossed is daunting. It would require not just net zero emissions, but net negative emissions—removing more carbon from the atmosphere than is emitted. Currently, the world’s nature-based carbon removal efforts, such as reforestation and peatland restoration, sequester about 2.2 billion tons of CO2 each year. But to reduce global temperature by just 0.1°C in a single year, this figure would need to increase one hundredfold. “Let’s say if we go to 1.6°C and we want to drop down to 1.5°C—we need to remove around 220 billion metric tons of carbon dioxide,” Zickfeld said. Given land constraints and competing demands, scaling up nature-based solutions to this extent is virtually impossible, making technological carbon capture essential.
However, as Robin Lamboll, a climate researcher at Imperial College London, pointed out, negative emissions technologies are still expensive, largely unproven at scale, and unlikely to deliver more than net zero in the near future. “In practice we will be doing quite well if we find that the rollout of these technologies does any more than bring us to net zero,” Lamboll told Live Science. Even in the most optimistic scenario, cooling the planet after overshooting would be a slow process—perhaps just 0.3°C over 50 years.
Meanwhile, the world’s biggest fossil fuel companies continue to shape the policy debate. In an exclusive interview with The Australian, Chevron’s CEO Mike Wirth argued that Australia should emulate the US and Middle East to attract more fossil fuel investment. Wirth, fresh from a private meeting with Deputy Prime Minister Richard Marles, made his case for lower regulation and greater support for oil and gas. Chevron, which reported $9 billion in earnings over the past six months, has faced rising costs in Australia due to legal challenges, labor rules, and changes to the Petroleum Resource Rent Tax.
The Australian’s coverage, as noted by The Guardian, did not mention climate crisis concerns or Chevron’s record on greenhouse emissions. This omission is striking given that Chevron’s Gorgon LNG plant in Western Australia is the country’s largest single source of emissions, and that the company has received millions of dollars in carbon credits under Australia’s safeguard mechanism. Historically, Chevron has been responsible for more greenhouse gas emissions than any other independently owned entity, trailing only Saudi Aramco, China, and the former Soviet Union.
Wirth’s call for Australia to be more like the US or Middle East comes against a backdrop of regulatory rollbacks in the US under former President Donald Trump. The Environmental Protection Agency, led by Lee Zeldin, described a wave of deregulation as the “greatest day of deregulation our nation has seen.” Trump’s administration withdrew the US from the Paris Agreement, dismissed climate science, and sought to rescind regulations limiting greenhouse gas emissions. Critics argue that such policies undermine global efforts to address climate change and ignore the mounting scientific consensus.
Chevron’s critics, including Alex Hillman of the Australasian Centre for Corporate Responsibility, contend that the company’s real challenge isn’t regulation but the growing competitiveness of renewables. “The biggest obstacle for fossil fuel companies like Chevron is not government regulation, but that renewables are increasingly out-competing LNG on cost and offering real energy security for emerging markets,” Hillman told The Guardian. Advocacy groups have also lambasted Chevron’s climate targets as insufficient, pointing to the company’s stated goal to “grow our oil and gas business” as fundamentally incompatible with global climate goals.
Despite the grim outlook, there are glimmers of hope. Michael Mann noted in a June interview with BBC World News America, “Let’s recognize that we’re starting to turn the corner.” The world is making progress on emissions reductions, but the window to avoid the worst impacts is closing fast. The carbon budgets for staying below 1.6°C, 1.7°C, and 2°C could be used up within seven, twelve, and twenty-five years, respectively, if current emission rates persist.
For now, the message from scientists is clear: rapid, decisive action is the only way to avert escalating climate risks. Each fraction of a degree matters—and the choices made by policymakers, industry leaders, and citizens in the coming years will determine the planet’s trajectory for generations to come.
