{"id":47150,"date":"2016-12-08T17:35:41","date_gmt":"2016-12-08T23:35:41","guid":{"rendered":"http:\/\/news.medill.northwestern.edu\/chicago\/?p=47150"},"modified":"2016-12-16T15:58:43","modified_gmt":"2016-12-16T21:58:43","slug":"climate-scientists-gather-to-tackle-urgent-challenges-for-the-planet","status":"publish","type":"post","link":"https:\/\/news.medill.northwestern.edu\/chicago\/climate-scientists-gather-to-tackle-urgent-challenges-for-the-planet\/","title":{"rendered":"Climate scientists gather to tackle urgent challenges for the planet"},"content":{"rendered":"

By Janice Cantieri<\/strong><\/p>\n

\u201cYou can\u2019t open a McDonald\u2019s ketchup packet without the little notch. Try it, okay?\u201d noted climatologist Richard Alley.<\/p>\n

Without the little notches, plastic ketchup packets are almost impossible to open no matter how much you pull or tear. Cracks in the world\u2019s ice sheets are like those little notches, Alley said. Once these cracks appear in ice sheets, the stress concentrates there and eventually can lead to large sections of ice falling off and melting quickly.<\/p>\n

Alley, professor of geosciences at Pennsylvania State University, used the analogy to describe how ice sheets can rapidly break apart due to preexisting \u201ccracks\u201d or \u201cnotches\u201d in the ice produced when meltwater opens small crevices and then makes them big ones, he said. \u201cWhen you make these cracks bigger, it makes [the ice sheet] break way faster,\u201d Alley said\u00a0at this year\u2019s Comer Abrupt Climate Change Conference<\/a>.<\/p>\n

Alley and a gathering of the world\u2019s top geologists, paleoclimatologists, engineers and climate modelers meet each fall in southwestern Wisconsin to discuss their most recent discoveries on the origins and consequences of abrupt climate change.<\/p>\n

<\/p>\n

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Richard Alley showed how rapid sea level increases\u00a0can occur as a result of cracks in the earth’s ice sheets. (Janice Cantieri\/MEDILL).<\/figcaption><\/figure>\n

\u201cWe know what nature can do, so we know that climate change is a big deal, and we know that what humans are doing now is not natural,\u201d Alley said. \u201cAcross almost anything that we look at, the first degree of warming had very small costs, but we\u2019ve done that. The second degree of warming will have larger costs. We\u2019re mostly committed to that. The third degree of warming will have even larger costs.\u201d<\/p>\n

Alley emphasized<\/a> the fact that the Pentagon prioritizes climate change as a national security issue, and that adapting to a sustainable energy system is beneficial for the economy.<\/p>\n

The key question the scientists addressed at this year\u2019s conference was urgent – \u201cnot whether or not global warming and climate change is happening, but how fast,” said Philip Conkling, a sustainability consultant and author. \u201cTo understand that, we have to understand the dynamics of the past.\u201d<\/p>\n

Field research took many of the scientists around the world and deep into the history of Earth\u2019s climate in order to better understand the sensitivities and \u201cswitches\u201d that triggered abrupt changes thousands and even millions of years ago. Piecing together these discoveries provides a progression of natural events to compare to the changes occurring today at an accelerating rate as a result of human impacts.<\/p>\n

Joerg Schaefer, a geochemist at Columbia University, presented the latest findings on the threat to the stability of the melting\u00a0 Greenland ice sheet, which holds an equivalent of about 7 meters of sea level rise (about 23 feet), enough to inundate many coastal cities.<\/p>\n

\u201cThe Greenland Ice Sheet was most certainly gone during natural forcing [in the past] and of course this is also worrisome because what we are doing in the moment will almost certainly at one point, and maybe soon, deglaciate Greenland. So it\u2019s really pressing that we understand these processes quickly,\u201d Schaefer said.<\/p>\n

The problem is that human use of fossil fuels is moving global climate much faster than nature does, several scientists said.<\/p>\n

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The Greenland Ice Sheet was deglaciated in the past due to natural processes, which is worrisome, Joerg Schaefer said, because humans’ current carbon emissions could likely force a modern deglaciation. (Image: NASA)<\/figcaption><\/figure>\n

In order to avoid significant sea level rise, droughts, food shortages, disease, and international conflicts, the world must cut carbon dioxide emissions by more than a factor of 10, said pioneering climate scientist Wallace Broecker of Columbia University.<\/p>\n

\u201cEvery ounce of CO2<\/sub> we put in the atmosphere makes it a little bit worse. We see things happening already and obviously. As we warm the planet up more those things are going to get bigger and extend further,\u201d he said. \u201cWe\u2019ll start to see whether sea level will start to rise at a bad pace. It\u2019s going to move ecology everywhere.\u201d<\/p>\n