by Judith Curry
Chasing Ice is the story of one man’s mission to change the tide of history by gathering undeniable evidence of our changing planet.
Chasing Ice is a documentary that was screened at the White House for Earth Day in 2013. The film has won numerous awards:
Chasing Ice is the recipient of the Renewable Natural Resources Foundation’s 2013 Outstanding Achievement Award, and has won over 30 awards at film festivals around the world, including: SUNDANCE FILM FESTIVAL – Excellence in Cinematography Award: US Documentary The Environmental Media Association’s 22nd Annual BEST DOCUMENTARY AWARD.
In the spring of 2005, acclaimed environmental photographer James Balog headed to the Arctic on a tricky assignment for National Geographic: to capture images to help tell the story of the Earth’s changing climate. Even with a scientific upbringing, Balog had been a skeptic about climate change. But that first trip north opened his eyes to the biggest story in human history and sparked a challenge within him that would put his career and his very well-being at risk.
Chasing Ice is the story of one man’s mission to change the tide of history by gathering undeniable evidence of our changing planet. Within months of that first trip to Iceland, the photographer conceived the boldest expedition of his life: The Extreme Ice Survey. With a band of young adventurers in tow, Balog began deploying revolutionary time-lapse cameras across the brutal Arctic to capture a multi-year record of the world’s changing glaciers.
As the debate polarizes America and the intensity of natural disasters ramps up globally, Balog finds himself at the end of his tether. Battling untested technology in subzero conditions, he comes face to face with his own mortality. It takes years for Balog to see the fruits of his labor. His hauntingly beautiful videos compress years into seconds and capture ancient mountains of ice in motion as they disappear at a breathtaking rate. Chasing Ice depicts a photographer trying to deliver evidence and hope to our carbon-powered planet.
The movie has stunning videography of the greenland ice sheet (check out the trailer), and includes includes scenes from a glacier calving event, lasting 75 minutes, the longest such event ever captured on film. James Balog’s story and quest is truly amazing, and he is an interesting and likable character. I was much less impressed by the obligatory ‘alarmism’ from some scientists, including Terry Root claiming that we will see a mass extinction event within 300 years, damaging hurricanes and attribution to AGW of the increase in global economic losses from extreme weather (something even the IPCC SREX has disavowed).
Last night, the School of Earth and Atmospheric Sciences at Georgia Tech hosted a screening of the documentary. The event was convened by Kim Cobb, who organized a panel of scientists to answer questions after the film. About 100 people attended the event, most of whom were from the nearby community (maybe 20% Georgia Tech folks). We had the full spectrum in the audience, ranging from a group from the Climate Coalition to someone affiliated with the Heartland Institute. I think the event was very rewarding for everyone involved; the Q&A lasted for 90 minutes and about a dozen people remained another 30 minutes for discussion.
The second question from the audience Q&A is the main focus for this post, it was something like this:
How much did that iceberg contribute to global sea level rise, and to what extent did that influence the storm surge and subsequent damage from Hurricane Sandy?
The story line of the film is something like this. A lot of people are skeptical about global warming, even Balog was skeptical. But Balog became convinced of CAGW by what was going on with NH glaciers, which he documents. His team’s capture of the calving event was a vindication. All this was then followed by the testimony of climate scientists about concerns/dangers of AGW. Hence, the audience was left with the impression that the iceberg filmed by Balog was somehow an exceptional event, and that the calving iceberg reflected dangerous climate change.
I provided this context for the question. As per the Wikipedia, calving of Greenland’s glaciers produce 12,000 to 15,000 icebergs each year alone. As for the issue of whether Balog’s iceberg was anything special, it was estimated that the iceberg had a volume of 7.4 cubic km. Compare this with with the Aug 2010 iceberg from the Peterman Glacier in northwest Greenland, that was estimated to be 260 square km.
Greenland mass balance
And what of the overall mass balance of the Greenland glaciers? Here is what the IPCC AR5 has to say:
The average rate of ice loss from the Greenland ice sheet has very likely substantially increased from 34 [–6 to 74] Gt yr–1 over the period 1992–2001 to 215 [157 to 274] Gt yr–1 over the period 2002–2011.
A paper that I find particularly illuminating on this topic is Timing and origin of recent regional ice loss in Greenland, by Sasgen et al. Excerpt:
Within the last decade,the Greenland ice sheet (GrIS) and its surroundings have experienced record high surface temperatures, ice sheet melt extent and record-low summer sea-ice extent. Using three independent datasets,we derive, for the first time, consistent ice-mass trends and temporal variations within seven major drainage basins from gravity fields from GRACE, InSAR together with output of the regional atmospheric climate modelling, and surface-elevation changes from the ICESat. We show that changing ice discharge (D), surface melting and subsequent run-off (M/R) and precipitation (P) all contribute, in a complex and regionally variable interplay, to the increasingly negative mass balance of the GrIS observed within the last decade. Interannual variability in P along the northwest and west coasts of the GrIS largely explains the apparent regional mass loss increase during 2002–2010,and obscures increasing M/R and D since the 1990s. In winter 2002/2003 and 2008/2009, accumulation anomalies in the east andsoutheast temporarily outweighed the losses by M/R and D that prevailed during 2003–2008, and after summer 2010.
Ok, so what about prior to 2002?
For all regions and the GrIS as a whole, the trends imposed by anomalies in M/R and D after 9-yr (2002–2011) significantly exceed decadal variability of trends in P for 1958–2010, meaning that GRACE and ICESat record long-term changes of the GrIS. For the west and northwest (basins F and G, respectively), the joint acceleration of M/R and D, significantly exceed the interannual variability in P, suggesting that, despite a strong contribution of P, 9-yr of GRACE data contain a long-term climate signal of mass loss acceleration in these regions.
Suggestive. But what about prior to 1958? Interesting paper by Csatho et al. titled Intermittent thinning of Jakoshavn Isbrae West Greenland since the Little Ice Age. From abstract:
Rapid thinning and velocity increase on major Greenland outlet glaciers during the last two decades may indicate that these glaciers became unstable, with terminus retreat leading to increased discharge from the interior and consequent further thinning and retreat. To assess whether recent trends deviate from longer-term behavior, we measured glacier surface elevations and terminus positions for Jakobshavn Isbræ, West Greenland, using historical photographs acquired in 1944, 1953, 1959, 1964 and 1985. These results were combined with data from historical records, aerial photographs, ground surveys, airborne laser altimetry and field mapping of lateral moraines and trimlines, to reconstruct the history of changes since the Little Ice Age (LIA). We identified three periods of rapid thinning since the LIA: 1902–13, 1930–59 and 1999–present.
And to what do we attribute the recent decline in Greenland ice mass? Some glaciologists are quick to attribute this AGW (e.g. Jason Box). Others stay away from the AGW issue (link): “It is hard to say. There are just so many factors that could play a role.”
I have argued that the argument put forward by Balog in Chasing Ice is misleading, leading the audience to infer dangerous anthropogenic climate change from this iceberg calving event. If we judge this by the standards of ethical framing of the climate debate, I would say that this movie falls pretty short. Was it good theater? Definitely yes. Will it grab people and make them worry about AGW, will it change the tide of history? I doubt it; the Greenland glaciers are just too remote (I think people had a more visceral reaction to Hurricane Katrina). The good news (for everybody) is that Balog is much more likable than Al Gore in Inconvenient Truth.