On the move

by Guest Blogger

July 5, 2005

We are getting ready to head out after a successful three days of

research and documentation in this area. Gordon and Leigh, our guest

scientists from the University of Maine, seem well satisfied with the

data they collected. After analysis they should have a clearer picture

of how these glaciers are reacting to warming temperatures. Getting

this data wasn’t easy though, or without risk.

To understand the danger involved in glacier work, you need to first

know a few things about the nature of glaciers – mainly that they move,

or rather, flow. That is, the ice of a glacier flows downhill somewhat

like water, only much more slowly. Being ice, it doesn’t act just like

liquid water. Deep cracks and ridges form – especially towards the

front (terminus) of the glacier where both of the ones they studied here

flow the fastest.

As the Australian Antarctic Division’s Field Manual

puts it, “Crevasses are caused by the inelasticity of ice and snow. As

the ice flows over obstructions or changes in the underlying terrain, it

splits and cracks.”

Think of water flowing over a rock in a fast

stream. Now imagine if that water froze in an instant, but by the sheer

mass of it still kept slowly moving.

Some details of the work

Different glaciers flow at different speeds. The interesting question

is whether these glaciers are moving faster now than they have historically.

In some

cases, glacier speed can be measured by satellite (this is part of

Leigh’s work), but in this instance the front of the glaciers are moving

too quickly (roughly 10 meters per day) to be measured with periodic

satellite overpasses – so on the ground data is needed.

To get this data, the science team use Global Positioning System (GPS)

receivers, which get positioning information from between four and

twelve satellites at a once – allowing for precision of up to one

centimeter (.39 inches) after processing the data.

First the team deploys a static receiver on stable rock, to be used as a

stationary reference point. Then five more receivers, with mushroom

like antennas mounted on copper pipes drilled into the ice, are placed

across the glacier.

To do this the team is brought on site by

helicopter because ice this close to its front, the glacier is so

riddled with crevasses, some hundreds of feet deep, it would be

impossible (or nearly suicidal anyway) to cross by foot.

How and where

“Landing” might not be the exact right word for what Hughie (pilot) has

to do on such uneven and potentially unstable ice. Perching maybe, or

“hovering exactly at ground level” is a more accurate description.

Hughie picks the location itself carefully with input from John

(logistics) or Gordon, who both have extensive professional experience

in glacier work. The site needs to be big enough to set up the

equipment at least a short distance from the helicopter, to minimize

blow down from the propellers. It also has to be at least somewhat

flat, and ideally will be slightly bowl shaped to keep people from

slipping over an edge. One fortunate thing is that there is little

snow in this wind swept part of the glacier since it’s summer – so at

least the cracks and crevasses are visible. No one goes any closer to

the edge than is absolutely necessary, or stays on the ice one minute

longer than they need to. In reality, the area they have to work with

is often smaller than the hold of our ship, say 50 feet (15m) by 30 feet

(10m), and the team usually gets their work done in under 15 minutes.

The entire deployment process has to be done twice for each glacier.

Each unit stays out for an hour or two, gathering positioning data,

before being retrieved. Twelve hours later the units are re-deployed in

the exact same locations on the ice (marked by pink flagging tape,

yellow leftover banner material and the antenna poles).

The ice in

this part of the glacier is too unstable to risk leaving the equipment

out there for too long. After the second set of data is collected,

everything is removed from the site.

Why it’s safe

It isn’t safe, not really. However, a combination of experience,

training, proper equipment, and careful planning reduces the amount of

risk to a small and reasonable level.

That said, there still is a certain element of danger that each member

of the team has made a personal decision to accept because they believe

in the importance of the work.

We are all driven to expand the base of

knowledge about global warming – a base of knowledge that scientists

world wide now agree indicates human induced global warming. The more

we know about how fast our planet is heating up, and the impacts this

will have, the better our chances of getting business and political

leaders to take real action.

This is an urgent matter, and time is not

on our side. Help is needed around the world, but because the U.S. is the

world’s largest per capita global warming emitter, we are making an

extra effort to mobilize people there. If you are a U.S. citizen, join the

Thin Ice Contest.

– Andrew

We Need Your Voice. Join Us!

Want to learn more about tax-deductible giving, donating stock and estate planning?

Visit Greenpeace Fund, a nonprofit, 501(c)(3) charitable entity created to increase public awareness and understanding of environmental issues through research, the media and educational programs.