The AUV SeaBED robot under the Antarctic sea ice (Photo : WHOI).
A new robotic study conducted by a coalition of scientist from the United Kingdom, Australia and United States has shown that the Antarctic sea ice is thicker than previously thought.
The SeaBED autonomous underwater vehicle (AUV) has allowed for more in-depth sea ice analysis than scientists have previously been able to garner from drill data measurements, ship visual measurements (that are unable to access thicker areas) and satellite images (snow cover hinders analysis of images) alone. SeaBED is able to access areas that have previously been inaccessible to researchers.
The SeaBED AUV from Woods Hole Oceanographic Institution (WHOI) is fitted with a camera that enables it to map the underside of the sea ice. Maps were made of three regions of the continent; Weddell, Bellingshausen, and the Wilkes Land. The robot covered an area of 500,000 square metres, the size of 100 football pitches.
Scientist found that the sea ice has an average thickness of between 1.4 meters and 5.5 meters, with some areas having a maximum ice thickness of 17 meters. 76 percent of the ice that was mapped was found to be deformed, this suggests that over the winter period the ice floes repeatedly collided to create a large denser body of ice (“This is in contrast to what scientists previously understood from the Arctic, where larger sections of sea ice, under constant pressure, produce longer linear ‘ridge’ features.“).
Dr. Guy Williams from Institute of Antarctic and Marine Studies adds (co-author on the paper) adds that:
The report is very, very long. Even the systhesis report which is an overview of the knowledge comes in at 116 pages.
So what key points can we take away from it?
“Human influence on the climate system is clear, and recent anthropogenic emissions of greenhouse gases are the highest in history. Recent climate changes have had widespread impacts on human and natural systems.”
This is to say that YES climate change has been driven by human influence and human resource use and exploitation. There is no hiding from it (though some will hide) we are responsible for global climate change.
Anthropogenic Greenhouse Gas Emissions since the 1970’s. You can clearly see that they are increasing and have risen more rapidly between 2000-2010 than in the previous three decades. (Graphic: IPCC).
What we know since the 1950’s is:
Snow and ice cover has been diminished.
Sea levels have risen.
The ocean and atmosphere are both warmer.
These are all at levels unprecedented over decades to millennia! This is not just normal fluctuations.
The Oceans have been the dominant warming environment. The largest increases have been in top 75 metres of the water column but increases have been measure at all depths including over 3000 metres (where estimates only began in 1992). In addition to this the ocean is also becoming more saline and far more acidic. In addition to the ocean warming there is also evidence that in coastal waters the oxygen concentration has decreased (warm water can hold less dissolved oxygen) as well which, is detrimental to coastal dependent species and reefs. If like me you are super interested int he ocean and the consequences for it you can browse the whole Ocean Observations Chapter.
Sea Levels have also risen in the period between 1901 and 2010. The mean rate of this sea level rise (very likely) was 1.7 [1.5 to 1.9] mm yr–1 between 1901 and 2010 and this increased to 3.2 [2.8 to 3.6] mm yr–1 between 1993 and 2010. Almost worldwide glaciers have been shrinking and the melting of sea ice has been contributing to the rise in sea levels.
What about the Atmosphere I hear you shouting…well in a very unsurprising turn of events it is also getting warmer.
“Each of the last three decades has been successively warmer at the Earth’s surface than any preceding decade since 1850.”
What are the causes of all this change:
“It is extremely likely that more than half of the observed increase in global average surface temperature from 1951 to 2010 was caused by the anthropogenic increase in greenhouse gas concentrations and other anthropogenic forcings together”