New Study Challenges 2 Degree Climate Change Cap

New studies published this week challenge the 2 degree Celsius global warming threshold and call for an early warning system to monitor climate shifts.

1 minute read

December 4, 2013, 1:00 PM PST

By Jonathan Nettler @nettsj


"Ever since the 2009 climate talks in Copenhagen, world leaders have agreed on 2 degrees Celsius (3.6 degrees F) as the maximum acceptable global warming above pre-industrial levels to avert the worst impacts of climate change (today we’re at about 0.8 degrees C)," writes Tim McDonnell. "But a new study, led by climatologist James Hansen of Columbia University, argues that pollution plans aimed at that target would still result in 'disastrous consequences,' from rampant sea-level rise to widespread extinction."

The study, which was co-authored by Columbia economist Jeffrey Sachs and published in the journal PLOS ONE, concludes that "[f]ossil fuel emissions must be kept to [500 billion metric tons] and global warming held to about 1.8 degrees to avert disastrous consequences," notes Tony Barboza in the Los Angeles Times

Barbosa also looks at a new National Research Council report that raises the spectre of sudden shifts in natural and human systems resulting from changes to the climate. To prepare for such threats, the report "[calls] for an early warning system to anticipate sudden climate shifts."

"'We watch our streets, we watch our banks ... but we do not watch our environment with the same amount of care and zeal,' said James White, a climatologist at the University of Colorado, Boulder and chairman of the committee that wrote the report."

Wednesday, December 4, 2013 in Grist

portrait of professional woman

I love the variety of courses, many practical, and all richly illustrated. They have inspired many ideas that I've applied in practice, and in my own teaching. Mary G., Urban Planner

I love the variety of courses, many practical, and all richly illustrated. They have inspired many ideas that I've applied in practice, and in my own teaching.

Mary G., Urban Planner

Cover CM Credits, Earn Certificates, Push Your Career Forward

Logo for Planetizen Federal Action Tracker with black and white image of U.S. Capitol with water ripple overlay.

Planetizen Federal Action Tracker

A weekly monitor of how Trump’s orders and actions are impacting planners and planning in America.

July 2, 2025 - Diana Ionescu

Aerial view of town of Wailuku in Maui, Hawaii with mountains in background against cloudy sunset sky.

Maui's Vacation Rental Debate Turns Ugly

Verbal attacks, misinformation campaigns and fistfights plague a high-stakes debate to convert thousands of vacation rentals into long-term housing.

July 1, 2025 - Honolulu Civil Beat

Person wearing mask walking through temporary outdoor dining setup lined with bistro lights at dusk in New York City.

Restaurant Patios Were a Pandemic Win — Why Were They so Hard to Keep?

Social distancing requirements and changes in travel patterns prompted cities to pilot new uses for street and sidewalk space. Then it got complicated.

June 19, 2025 - Diana Ionescu

Aerial view of new neifhborhood under construction with enpty lots in foreground.

In California Battle of Housing vs. Environment, Housing Just Won

A new state law significantly limits the power of CEQA, an environmental review law that served as a powerful tool for blocking new development.

July 2 - CALmatters

Low-rise Pearl Sreet mall in Boulfer, Colorado.

Boulder Eliminates Parking Minimums Citywide

Officials estimate the cost of building a single underground parking space at up to $100,000.

July 2 - Boulder Reporting Lab

Two-story buildings with porches in walkable Florida neighborhood.

Orange County, Florida Adopts Largest US “Sprawl Repair” Code

The ‘Orange Code’ seeks to rectify decades of sprawl-inducing, car-oriented development.

July 2 - CNU Public Square