By Daniel Brouse and Sidd Mukherjee
August 25, 2023
Updated: July 2025
When we began our climate experiments in the 1990s, we assumed significant change would occur over millennia. If climate change progressed linearly, this would hold. However, by the late 1990s, our findings--and global observations--began to show that climate impacts were accelerating exponentially.
Doubling time -- the period required for a quantity to double -- is a critical marker of exponential growth. For anthropogenic climate impacts, this period has collapsed at an alarming rate. By 2020, the doubling time for key impacts such as sea level rise had shrunk from 100 years to just 10 years, with rates increasing from about 1.5 mm/year to over 3 mm/year. If left unchecked, this trajectory could result in sea-level increases of up to one foot per year by 2050.
Extreme weather events are intensifying and occurring with alarming frequency as warming oceans, disrupted jet streams, and accelerating atmospheric rivers destabilize the climate system. What were once "500-year" events now occur every 5-10 years, and in many places, annually.
Non-linear acceleration is now confirmed: The 2-7°F rise in temperatures during recent European heatwaves translated to a tripling of heat deaths, demonstrating the amplified sensitivity of human and natural systems to seemingly small increases in mean temperatures. For every 1°C (1.8°F) increase, the atmosphere can hold 7% more water vapor, intensifying storms and the humidity of heatwaves, compounding mortality risk.
Originally estimated at 100 years, the climate doubling period--how quickly climate impacts double in intensity--contracted to 10 years. By 2024, new observations confirmed the doubling period had shortened further to just 2 years. 100 years → 10 years → 2 years. This means the damage caused by climate change today is already double what it was just two years ago. If this trend continues, it could be four times worse in two years, eight times worse in four years, and up to 64 times worse within a decade. Critically, these estimates are conservative, assuming the doubling period does not continue to shrink even further as tipping points and feedback loops accelerate the crisis.
The surge in persistent heat domes and resonance patterns in the jet stream confirms that critical thresholds in the climate system are being crossed faster than models predicted. As warming oceans and a destabilized jet stream lock in planetary wave patterns, heat domes and extreme weather events persist longer, amplifying both frequency and intensity.
In 2023, Earth's surface temperatures averaged over 3°C above pre-industrial levels--double the Paris Agreement's 1.5°C ceiling. Scientists agree that a 2°C rise will trigger tipping points and feedback loops, releasing carbon from permafrost, weakening the AMOC, and destabilizing polar ice sheets. This cascading "Domino Effect" could push global temperatures toward 6°C, rendering large regions of the planet uninhabitable within this century.
As climate change accelerates, what was once a 1,000-year flood now occurs as a 100-year or even 10-year event. Violent rain, flash flooding, and catastrophic water events are rewriting our understanding of "normal," with Chapel Hill's recent "1,000-year" flood serving as a stark warning that the climate system is entering a phase of nonlinear, runaway change that threatens human systems, infrastructure, and global stability.
Hawaii Governor Josh Green: "We've had six fire emergencies this August alone, equal to the number we had from 1953 to 2003. Climate change is here, with a hotter planet and fiercer storms."
Dr. Caroline Holmes, British Antarctic Survey: "We expected change, but not this much, and not this fast."
Jeff Boyne, NWS Climatologist: "The planet is warming so fast that climate normals now require updating every 10 to 15 years--ENSO regions every 5 years."
Walter Meier, NSIDC: "It's so far outside anything we've seen, it's almost mind-blowing."
Zeke Hausfather, Berkeley Earth: "September was, in my professional opinion as a climate scientist, absolutely gobsmackingly bananas."
Dr. James E. Hansen's recent paper, Global Warming Acceleration: Impact on Sea Ice, confirms our theory of underestimated climate sensitivity and feedbacks in traditional models. Hansen warns that, at current emissions levels, warming could exceed 7°C by 2100, crossing irreversible tipping points.
Our latest climate model projects global temperatures could rise by up to 9°C within this century, far exceeding older models predicting 4°C over a thousand years. This level of warming would cause mass migration, agricultural collapse, and wet-bulb temperatures in many regions that surpass human physiological limits, rendering survival impossible without radical adaptation.
Read more on wet-bulb temperatures and survival thresholds here.
Immediate, radical mitigation and adaptation efforts are now essential to preserve habitable zones, public health, and food systems in the face of cascading climate collapse.