Michael Mann: How Close Are We to 'Dangerous' Planetary Warming?
In the wake of the COP 21 UN climate summit in Paris, a number of important questions still remain unanswered. Take for example the commitment reached by the 197 participating nations to limit warming below the "dangerous" level of 2C relative to pre-industrial time (neglecting for the time being the aspirational goal of a substantially lower 1.5C limit acknowledged in recognition of the danger posed to low-lying island nations). The question immediately arises: How much time do we have until we reach the danger zone? How close are we to the 2C warming limit?
It has been widely reported that 2015 will be the first year where temperatures climbed to 1C above the pre-industrial. That might make it seem like we've got quite a ways to go until we breach the 2C limit. But the claim is wrong. We exceeded 1C warming more than a decade ago. The problem is that here, and elsewhere, an inappropriate baseline has been invoked for defining the "pre-industrial." The warming was measured relative to the average over the latter half of the 19th century (1850-1900). In other words, the base year implicitly used to define "pre-industrial" conditions is 1875, the mid-point of that interval. Yet the industrial revolution and the rise in atmospheric CO2 concentrations associated with it, began more than a century earlier.
Unfortunately, even the Intergovernmental Panel on Climate Change (IPCC) has fallen victim to this problematic convention in their latest (5th) assessment report. The key graphic (Fig. 1 below) in the Summary for Policy Makers ("SPM") of the report measures net anthropogenic (i.e. human-generated) carbon emissions and the resulting warming that can be expected. Both the emissions and warming and measured relative to an 1870 baseline.
The various future emissions scenarios are called "RCP"s (for "Representative Concentration Pathways") and they reflect varying assumptions regarding our future efforts to limit carbon emissions. The "RCP 2.6" scenario (dark blue), the most aggressive of the scenarios (from the standpoint of ramping down carbon emissions), corresponds to limiting net carbon emissions to about 3000 Gigatons (3 trillion tons) of CO2. We've already burned through about 2,000 Gigatons, i.e. we have expended two thirds of our apparent "carbon budget."
Achieving those limits in emissions would in turn limit maximum atmospheric CO2 concentrations to just under 450 parts per million ("ppm"). Pre-industrial levels were about 280 ppm. Current levels are just above 400 ppm and increasing by about 2.1 ppm per year. At that rate, we'll reach 450 ppm in a little over two decades. So obviously we need to reduce our carbon emissions rather rapidly if we are to avoid crossing the 450 ppm threshold.
The IPCC graphic suggests that keeping net CO2 emissions below 3 trillion tons—and thereby stabilizing maximum CO2 concentrations below 450 ppm—would likely keep warming below the "dangerous" 2C limit. Unfortunately, that conclusion is overly optimistic because, once again, it relies on the use of an artificially warm, too-recent baseline for defining the pre-industrial period.
To better understand the problem, consider this graph (Fig. 2 below) from an article my colleagues and I published in the American Meteorological Society's Journal of Climate back in 2013.
Source: Schurer et al (2013)
The graph shows the warming of the Northern Hemisphere (in degrees C) due to human-generated greenhouse gases ("GHG") alone, as estimated by the various climate models used in the IPCC 5th assessment report (the black curve—the "multimodel mean" is the average over all of the climate model simulations that were done). The graph has been annotated to indicate the warming observed by 1800 and 1900. It is evident that roughly 0.3C greenhouse warming had already taken place by 1900, and roughly 0.2C warming by 1870. While that might seem like a minor amount of warming, it has significant implications for the challenge we face in stabilizing warming below 2C, let alone 1.5C, as we shall see below.
By Itai Vardi
A recent intensification in protests against Williams Partners' planned Atlantic Sunrise pipeline in Pennsylvania prompted a state senator to propose legislation aimed at limiting demonstrations.
Last month, Pennsylvania Sen. Scott Martin (R-Norman) announced his intention to introduce legislation that would pass the costs of law enforcement responding to protests onto the demonstrators. Martin also helped introduce a different bill that would criminalize protests at natural gas facilities.
The so-called "first and last mile" problem is one of the biggest hurdles with public transportation. How do you encourage more people to take Earth-friendlier commutes when their homes are miles away from the train or bus station?
One solution, as this Estonian electric scooter company proposes, is to simply take your commute with you—literally. Tallinn-based Stigo has developed a compact e-scooter that folds to the size of a rolling suitcase in about two seconds.
[Editor's note: I'm still in shock after hearing the news that Lucia Grenna passed away in her sleep last week. When we first met in April of 2014 at a Copenhagen hotel, I was immediately taken by here powerful presence. We spent the next couple days participating in a Sustainia climate change event where Lucia presented her audacious plans to connect people to the climate issue. I had the chance to partner with Lucia on several other projects throughout the years and work with her incredible Connect4Climate team. I was always in awe of her ability to "make the impossible possible." Her spirit will live on forever. — Stefanie Spear]
It is with a heavy heart that Connect4Climate announces the passing of its founder and leading light, Lucia Grenna. Lucia passed peacefully in her sleep on June 15, well before her time. We remember her for her leadership and extraordinary ability to motivate people to take on some of the greatest challenges of our time, not least climate change.
By Stacy Malkan
Neil deGrasse Tyson has inspired millions of people to care about science and imagine themselves as participants in the scientific process. What a hopeful sign it is to see young girls wearing t-shirts emblazoned with the words, "Forget princess, I want to be an astrophysicist."
As Trevor Noah noted during The Daily Show episode last night (starts at 2:25), the real reason Trump has these rallies is to "get back in front of his loyal crowds and feed of their energy." Noah believes that "Trump supporters are so on board with their dude he can say anything and they'll come along for the ride."
By Katie O'Reilly
Two years ago—long before coal became one of the most dominant and controversial symbols of the 2016 presidential election—Bloomberg Philanthropies approached production company RadicalMedia with the idea of creating a documentary exploring the U.S. coal mining industry. Last spring, they brought on Emmy-nominated director Michael Bonfiglio, tasked with forging a compelling story out of the multitudes of facts, statistics and narratives underlying the declining industry.