By Sidd Mukherjee and Daniel Brouse
November 22, 2025
In the 1990s, we developed what became known as The Non-Linear Acceleration Hypothesis--the proposition that climate change is not progressing linearly but is accelerating exponentially. Working together, with Sidd's background as a Doctor of Physics from Ohio State and my own experimental and observational analyses, we produced the foundational evidence for this theory. By the early 2000s, our work had evolved into a recognized climate framework, validated repeatedly through independent replication and supported by an expanding body of empirical data. Over the decades, this body of confirmation has solidified into the scientific consensus we see today.
One of the most compelling indicators of nonlinear acceleration is the dramatic contraction of the doubling time of climate impacts--the interval in which damage effectively doubles due to interacting feedback processes. In the mid-20th century, the doubling time was on the order of 100 years. By the early 2000s, it had fallen to 10 years, and recent analyses show that it has now plunged to approximately 2 years.
This means that the impacts of climate change today are twice as severe as they were two years ago. If the doubling time remains constant, they will be four times worse in two years, eight times worse in four years, and potentially sixty-four times worse within a decade. These estimates are conservative; the doubling period continues to shorten as feedbacks intensify. With no meaningful global mitigation underway, the trajectory is unmistakable and vastly more catastrophic than previously projected.
We have long regarded Dr. James E. Hansen as one of the principal founders of modern climate science. In April 2025, Hansen's paper Global Warming Acceleration: Impact on Sea Ice provided a direct, data-driven confirmation of our hypothesis. His analysis demonstrated that global warming is accelerating, and that climate sensitivity is higher than IPCC estimates, fundamentally altering expectations for 21st-century warming.
Hansen concluded that IPCC models underestimate both climate sensitivity and key feedback processes. Under current emissions levels, he projects that warming by 2100 is likely to exceed 7°C, dramatically raising the probability of crossing multiple climate tipping points.
In November 2025, Hansen, Kharecha, and Morgan published Warning! This "Colorful Chart" Is Censored by IPCC, offering further confirmation.
Their analysis centers on a chart showing the five-year running mean of the annual increase in greenhouse gas forcing. Over the past 15 years, they find that the rate of increase has surged to ~0.5 W/m2 per decade--far higher than IPCC projections. This acceleration is not reflected in IPCC scenarios and is fundamentally incompatible with its claims of remaining "pathways" to 1.5°C or 2°C.
Hansen and colleagues argue that the IPCC relies too heavily on Integrated Assessment Models (IAMs), which they describe as opaque "dark boxes"--tools that embed assumptions that are rarely examined in public-facing science.
They highlight that:
Hansen's findings, along with related analyses, suggest climate sensitivity in the range of 4-5°C per CO2 doubling, substantially above many IPCC estimates. They warn that without extraordinary action within the next 5-10 years, Earth could be locked into a high-warming trajectory that destabilizes major climate systems.
If Hansen et al. are correct, the window for avoiding catastrophic warming is significantly narrower than models suggest. Their work underscores the need for:
Their findings also increase the urgency of addressing the accelerating feedback loops we identified decades ago.
Building on nonlinear thermodynamics and chaos theory, we now know that climate tipping points are not isolated events--they interact. As major systems destabilize, they trigger secondary failures, creating a cascade of compounded impacts.
Our recent synthesis of 2024-2025 data shows:
* Our probabilistic, ensemble-based climate model -- which incorporates complex socio-economic and ecological feedback loops within a dynamic, nonlinear system -- projects that global temperatures are becoming unsustainable this century. This far exceeds earlier estimates of a 4°C rise over the next thousand years, highlighting a dramatic acceleration in global warming. We are now entering a phase of compound, cascading collapse, where climate, ecological, and societal systems destabilize through interlinked, self-reinforcing feedback loops.
What Can I Do?
The single most important action you can take to help address the climate crisis is simple: stop burning fossil fuels. There are numerous actions you can take to contribute to saving the planet. Each person bears the responsibility to minimize pollution, discontinue the use of fossil fuels, reduce consumption, and foster a culture of love and care. The Butterfly Effect illustrates that a small change in one area can lead to significant alterations in conditions anywhere on the globe. Hence, the frequently heard statement that a fluttering butterfly in China can cause a hurricane in the Atlantic. Be a butterfly and affect the world.