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 key indicator of exponential growth. By 2020, the doubling time for certain anthropogenic climate impacts had shrunk from 100 years to just 10 years. For example, sea level rise increased from about 1.5 mm/year to over 3 mm/year. If this continues unchecked, we could face sea-level increases of one foot per year by 2050.
Extreme weather events are intensifying and becoming more frequent due to warming oceans, disrupted jet streams, and accelerating atmospheric rivers. What were once rare "500-year" events are becoming 5-year or even annual occurrences.
If the climate doubling period continues to shrink, we could see a 200% increase in event intensity with a 28x increase in occurrence within the next decade.
According to NASA, global average sea level rose by approximately 0.3 inches (0.76 cm) from 2022 to 2023 alone. Initial projections anticipated a 10-year doubling period; new observations suggest it may have shrunk to as little as 2-5 years.
In 2023, Earth's surface temperatures averaged over 3°C above pre-industrial levels--double the Paris Agreement ceiling. Scientists agree that a 2°C rise would trigger tipping points and feedback loops, with further warming unleashing carbon from permafrost and collapsing critical systems, including the AMOC and polar ice caps. This cascading "Domino Effect" could push global temperatures towards 6°C, rendering large regions of the planet uninhabitable.
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.