Clues in the cryosphere

We are lucky to live on Earth – a unique planet providing everything necessary for a healthy and sustainable life. We can breathe fresh air, drink clean water, and grow the crops we need to survive. But with recent climate change, rising temperatures are changing our planet, and this creates new challenges for all living organisms. All of the natural elements of our planet are interconnected, so a change in our air or water at a global level will affect everything else, including plants, animals and people.

The Earth is composed of different physical systems that interact to influence the state of our planet. Our air is known as the atmosphere. All forms of water, including rivers, lakes and oceans, are called the hydrosphere. The rocks on the surface of our planet, and the core and mantle on the inside, make up the geosphere. The world of living things — from trees and grass, to mammals and birds, to reptiles and bacteria — is the biosphere.

The frozen part of the hydrosphere is called the cryosphere. The word “cryo” comes from the Greek word kruos, which means "freezing cold." The ice sheets in Antarctica and Greenland, mountain glaciers and floating sea ice are all part of the cryosphere. So is all the frozen ground on Earth, which is called permafrost. The cryosphere is an important place to look for evidence of our changing planet.

Most of the cryosphere is found in the northern Arctic regions (including Alaska, Finland, Greenland, Iceland, Siberia, and northern Canada) and the South Pole (Antarctica). The rest of it is located at high altitudes in mountains, including the Andes, Himalayas, and Rocky Mountains. Ice also forms on the ocean surface when it gets cold enough. Not surprisingly, this is called sea ice.

The Earth’s climate has gone through cold and warm periods throughout time. The most recent of these cold periods, called an ice age, happened during the Pleistocene Epoch. The Pleistocene began about 2 million years ago and ended around 12,000 years ago. Over the course of the Pleistocene, there were intervals of cold (glaciation) and warm (interglacial) phases. During the most recent and coldest phase of the Pleistocene, called the Last Glacial Period, there was a lot more ice on the Earth. Nearly 30% of the Earth’s land surface was covered by glaciers, including all of Canada and a good bit of the northern part of the United States. Today, about 10% of the Earth's surface is covered by glacial ice.


Everyone knows that freshwater freezes at 0° C (32° F). But did you know that the salt in seawater keeps it from freezing until it reaches a colder temperature? Seawater in the ocean freezes at around -2° C (28.4° F).




Baffin Island is in remote northeastern Canada. On Baffin is a high, rolling upland, with an average altitude of 4,500 to 6,000 feet. Around 120,000 years ago, after the last warm interglacial period of the Pleistocene ended, huge snowfields started to accumulate on this high area. An interglacial period is the time between ice ages when the climate warms.

Eventually, the snowfields thickened and turned into a series of ice caps. As the ice caps grew, they buried mosses growing around them in the tundra.

Today, the ice caps are melting quickly. Many of the ice caps are soon to disappear, and those mosses are coming into the light of day once again. Scientists from the University of Colorado’s Institute of Arctic and Alpine Research (INSTAAR), and Matt Kennedy from the EIS team, traveled to Baffin Island to see what was going on.

Using chemical dating methods — how much of an element called carbon-14 was present — the team was able to tell when the ice caps had grown large enough to bury the moss that is just coming back out into daylight today. Much of the moss they sampled had been buried by the ice for at least the past 40,000 years. In certain places, scientists found that some moss may have been buried for up to 120,000 years!

Incredibly enough, if the moss is given enough sunlight and moisture, it is capable of coming back to life. That’s even after it has been buried for tens of thousands of years in its grave under the ice! So the team nicknamed it “zombie moss.”


 What are glaciers?

Glaciers — huge masses of ice — are found all over the globe, from Alaska to Africa. They build up over time when more snow falls in winter than melts in summer. As the snow piles up, it gets compressed and hardens into ice. Ice can actually flow — it can bend like taffy. If a mass of ice forms on a mountaintop, it flows downhill.


Glaciers are found on every continent and even in the tropics. With our planet warming and snowfall patterns changing, glaciers are disappearing — and at an accelerating rate. Some glaciers have vanished entirely.



During the summer, glaciers flow further and faster than they do in winter. Many of them look like large frozen rivers – like this one, the Khumbu Glacier. It flows down from the world’s highest mountain, Mount Everest (8,847 meters or 29,028 feet), in Nepal.

Glaciers are important to people and the natural environment around them. In many places, they are recreational and tourist attractions for skiing, climbing and hiking. Glaciers are not just beautiful to look at; glaciers and snowfields also provide water for downstream communities.

Glaciers and snowfields hold a large reservoir of the world’s freshwater. Many people around the world depend on melting snow and ice for their drinking water, to irrigate crops, and for hydroelectrical power. This is true for many communities located in south and central Asia; along the spine of the Andes mountains of South America; in the western United States; in the provinces of British Columbia and Alberta in western Canada; and in central and southeastern Europe. Many kids living in the mountains of South America depend upon water coming from glaciers high up in the Andes, which also feeds into the Amazon river. Others living in Tibet get their water from rivers flowing down from the Himalaya glaciers. If you live in the western United States, you probably drink water that comes from snowmelt  in the Rocky Mountains.


Glacier: a long-lasting accumulation of snow that turns into flowing ice. Snowfield: an accumulation of winter snow that melts away in summer. Snowfields sometimes last for years, but they never pile up thick enough, or stay long enough, to turn into a glacier.


Glaciers, ice caps and snowfields around the world are sometimes called water towers, which means that they store and supply water for communities that live downstream. Many populations around the world are dependent on melt water from glaciers for agriculture (irrigation), drinking water, and hydropower. Glaciers are an especially important water resource during the dry season, when precipitation declines. The glaciers of the Himalayas are the main water towers for Central Asia, and provide water resources for about 1.5 billion people. In the Andesand Patagonia, glaciers are also important water towers that provide water services for several million people in both rural and urban centers across Peru, Bolivia, Ecuador, Columbia, Chile and Argentina. 


There are many different terms to describe various types of glacier ice. The largest and thickest bodies of glacier ice are ice sheets. The only two ice sheets on Earth today are found in Greenland and Antarctica. These are also called continental glaciers because they cover an enormous area of land. Smaller sheets of ice — up to about 52 square kilometers (20 square miles) — are called ice caps. Many ice caps are found in Iceland and the Canadian Arctic.

A mountain glacier is the most common form of glacier ice. They are found in the Rocky Mountains, western Canada, Alaska, the Alps, Scandinavia, the Andes, the Himalaya and New Zealand. Africa’s tallest peak, Mount Kilimanjaro, stands almost on the equator, but its summit (5,895 meters or 19,341 feet) is so high and cold that a few glaciers have even formed there. 

When ice flows off land, into the ocean and forms a floating platform, it is called an ice shelf. The world’s largest ice shelves are in Antarctica. Others are in Greenland and the Canadian Arctic. Sea ice is frozen seawater. The world’s largest expanse of sea ice covers the Arctic Ocean. Another large expanse encircles Antarctica like a necklace. 

When a large piece of ice breaks off from an ice shelf or glacier that runs into the ocean, it is called an iceberg. Greenland and Antarctica are the source of the vast majority of the world’s icebergs. Today’s satellites keep good track of icebergs so that ships don’t run into them.


 Glaciers grow and shrink:
 seeing climate change

If you see a glacier, it means that over many years in the past (often thousands of years), it was cold and snowy enough in the winter for ice to form and cool enough in the summer to keep it from melting away. The highest and coldest part of a glacier collects snow. This area is called the accumulation zone. The lowest and warmest part of a glacier, where the ice melts away, is called the ablation zone. The boundary between these two zones is called the equilibrium line. If the ablation is greater than the accumulation, then the glacier is retreating. Take a look at the picture above to learn more about glacier features.


In the time-lapse sequence below from EIS's AK-01 "Kadin" camera, we see that the Columbia Glacier, in Alaska, is retreating incredibly fast. In fact, it retreated so quickly, the camera had to be repositioned.

Glaciers are like thermometers for the local air temperature. They tell whether summers are getting hotter, staying the same, or getting colder.

If a glacier is staying about the same size, it tells us that the summer heat and winter cold are more or less in balance. In other words, the amount of snow falling in the winter is about the same as the amount of snow melting in the summer.

If a glacier is advancing or getting thicker, then the summertime air has been getting cooler — and more winter snow is falling than is melting in the summer. If a glacier is retreating and thinning, the summertime air is getting hotter — and more snow is melting in summer than is falling in winter.

What does it say when the vast majority of glaciers in the world are retreating and so many ice shelves, ice caps, and glaciers have disappeared in the past 100 years? It means that the summers are getting warmer and that the winter snowfall is less.

That’s what the Extreme Ice Survey time-lapse cameras document: the effect of warmer summers, and decreasing winter snowfall, on glaciers. This is an unmistakable sign of warming air temperatures. It’s just like a melting ice cube in your hands — it tells you how your body’s heat melts the ice.

Take a look at the time-lapse video of Columbia Glacier in Alaska. This video shows a massive amount of glacier melt over the period of 10 years. You'll also see in the photographs to the right that the entire glacier has been "deflating" just like letting air out of a balloon. Not only does ice melt at the edges of a glacier, but the ice also thins. Columbia Glacier has "deflated" more than the height of the Empire State Building in the last few decades.


 Secret messages in the ice

There are several kinds of scientists who gather clues to investigate our planet’s climate. Climatologists, meteorologists, biologists, anthropologists, glaciologists, and even photographers like James are among the many kinds of people who are studying climate change. One of the biggest clues giving us evidence of our changing planet is sealed in the ice of the glaciers.

Frozen in ice are clues about our climate’s past. Scientists drill into the glacier to collect samples of ice from long ago. The ice is collected in long cylinders. Each of these cylinders, or ice cores, holds tiny bubbles of air that were trapped every time new snow fell on the ice. Watch this video to see how ice cores are taken out of the glaciers for scientists to study.

Glacial ice recovered from the Greenland ice sheet can be as much as 400,000 years old, and from the Antarctic ice sheet it can be over two million years old! The air bubbles found in the ice cores are "time capsules" that hold samples of the air throughout the lifetime of the glacier. The bubbles allow us to look at the history of the air we breathe and reveal how temperature and CO2 have varied over the past several thousand years.

Scientists collect ice core samples from around the world to help improve our understanding of the planet’s climate. Unfortunately, some glaciers are retreating and thinning so quickly due to climate change that the record of our past climate is literally melting away.

  • Ice Core

    Ice Core

    Near Humboldt, North Greenland, scientist Dan McGrath holds 15 meter ice core, May 2010. Photo by Dan McGrath.


Bubbles of ancient air, possibly 15,000 years old, are released as the Greenland Ice Sheet melts. Trapped eons ago in snowstorms, bubbles of fossil air float to the surface of the melt water. There, they are temporarily trapped in the ice by a midnight freeze. By mid-morning of the following day, the sun's warmth melted the bubbles and released the ancient air back into our modern atmosphere. 

Scientists study the air that’s in the bubbles to identify which gases were present in the atmosphere long ago. The most important gas that scientists look for in the ice core samples is the one we hear of most when talking about climate change: carbon dioxide (CO2). Carbon dioxide is a colorless, odorless gas that is necessary for all life on Earth. Scientists can also tell what the local temperature of the air was by studying the amounts of different types of oxygen stored in the ice. By examining the concentration of these gases in the ancient air bubbles, scientists can see the alternating cycles of ice ages and warming phases on our planet.


Danish scientist Willi Dansgaard, along with the U.S. military, drilled down into the ice sheets on Greenland in 1964. They collected long cylinders of ice from glaciers that were 3.2 kilometers (2 miles) deep. Dansgaard analyzed these bubbles for isotopic concentrations. He was the first scientist to show that the climate history of our planet could be read from ice cores — and this work has been done over and over again by many women and men in the sciences since this discovery. In ice cores, the isotopic signature of oxygen (O) says a lot about Earth’s climate in the past, and whether it was warmer or colder in the past.

  • Air on Earth contains large amounts of nitrogen (~78%) and oxygen (~21%), along with small amounts of argon, carbon dioxide and other greenhouse gases.
  • Scientists know from examining the ice core bubbles that some gases like carbon dioxide (CO2), methane (CH4) and nitrous oxide (N2O) have increased substantially since 1850. These gases are known as greenhouse gases because they trap the sun’s heat close to the Earth’s surface, warming the Earth like a greenhouse.

The bubbles stored in the ice hold two major clues about our changing climate: CO2 and temperature. Examining these clues, scientists have found that CO2 and temperature are linked. In other words, when the CO2 levels rise, the temperature also rises. The bubbles in the ice are records of past air that help us understand how quickly our climate is changing. 



  • Scientists gather observations and immense amounts of data that help us understand the changes that have occurred in our climate over millions of years, including the atmosphere, hydrosphere, cryosphere, biosphere, and geosphere.
  • Glaciers are an important environmental indicator of our changing planet. Seeing and measuring glacier loss and melt alerts us to the rapid temperature warming on our planet as a result of climate change.
  • Scientists study the ancient air bubbles in glacier ice that store a record of Earth's past climate. It shows us that carbon dioxide in the air has been rising higher and faster than in the past.


 Chasing Ice Worldwide

The Extreme Ice Survey has set up time-lapse cameras all around the world to collect photographs of glacier changes. The cameras are protected in weatherproof housings mounted on sturdy tripod-like supports that are bolted to bedrock alongside the ice. Solar panels supply them energy. A little custom-made computer inside the housing tells the cameras when there’s enough light to take a picture, which is every 30 minutes during daylight hours.

Building and designing the cameras was really challenging. But James Balog was dedicated to keep experimenting until he got a system that worked. No one had ever built equipment designed to survive in such extreme weather conditions in very remote locations.

The cameras have to withstand winds of 150 miles per hour, temperatures of -40° Fahrenheit, deep snow and torrential rain. Take a look at this video to see an EIS time-lapse camera being assembled.

Once the cameras are assembled, they are ready to be placed in the field. Getting to the glacier location to install the camera can be quite an adventure, sometimes requiring a helicopter, huskies, and ice trekking with safety equipment to get there! After the time-lapse cameras have been installed, someone from the EIS team or partner organizations has to go back to the cameras at regular intervals to download the images. Take a look at this map to see the locations of past and present EIS time-lapse cameras that are keeping an eye on the changing landscape.

After the photographs are downloaded, the EIS team in Boulder, Colorado look through all the pictures taken by the time-lapse camera—each camera collects about 8,000 pictures per year—to build a good video sequence showing how each glacier has changed through time.

In many other places, James and the EIS team take “repeat” photographs. Some places don’t have time-lapse cameras installed but are still photographed to document change. James and the EIS team return to these locations on a regular basis to photograph the exact same landscape. These repeat photographs also help us see how the glacier has changed over time.

The EIS picture archive has more than a million pictures. It is an incredible visual record, with the cameras and the EIS team acting as witnesses, showing how our world has changed since the project started taking repeat pictures of glaciers in 2006 and time-lapse pictures in 2007.