1) Looking at the environment and the biology in the Arctic
To understand what is happening in the Arctic, we need to look at the environment and at the biology.
Important parts of the Arctic environment are: air, ocean, and ice (white in map on right). One kind of ice is sea ice. It is frozen ocean water that forms and melts with the seasons and is a crucial aspect of the Arctic environment. Much of Arctic sea ice actually never melts away in summer and survives year-round.
Animals and plants in the Arctic are mostly ice-dependent. For half of the year most of the Arctic is covered in sea ice.
One way we can learn about what has happened to the environment over time is to look at data about the atmosphere and sea ice.
We can also look to see if any changes in the animals and plants of the Arctic have happened during the same time. This can help us better understand overall what has been happening in the Arctic over time.
So let’s dive into some data!
2) Reading surface air temperature data
Scientists put thermometers all over the Arctic and use satellites to record the air temperature. From daily readings, scientists can put together the data from all over to get a sense of what the overall surface air temperature for the Arctic is. Scientists have been doing this since the 1940s.
Scientists rely on a small number of thermometers placed in the Arctic together with satellites to record the air temperature. From daily readings, scientists can put together the data from all over to get a sense of what the average surface air temperature for the Arctic is. Scientists have been doing this since the 1940s.
So we can look at the average surface air temperature each year from 1979 to 2016 to get an idea of how the Arctic is warming. Warming is important because it directly influences the amount of sea ice in the Arctic.
So let’s see what the data demonstrates…
3) Overall, what has happened to Arctic air temperature since 1980?
Look through the data of Arctic air temperature in the graph. What do you notice about the air temperature?
Now, watch it again. What do you notice about overall how the air temperature has changed?
If you change from 26ºC to 28ºC (79ºF to 82ºF), its hotter but the conditions don’t change too much. But if you change from -1ºC to +1ºC (30ºF to 34ºF) that means you cross over the freezing point of water, which means the conditions can change quite a bit.
To think about it another way, for a lot of the year air temperatures in parts of the Arctic are near when melting happens, so a change of 2 degree can be the difference between walking on ice or swimming in (very cold!) water.
Note, the Arctic has warmed faster than anywhere else on the planet. If you want to compare these changes in air temperature to global temperatures, click here
What else may be changing in the Arctic environment as the air temperature rises? Maybe sea ice…let’s look and find out.
4) Reading Summer Sea Ice extent data (September)
Scientists use daily satellite images to measure the extent of Arctic sea ice (how far out in all directions the sea ice reaches). From the daily satellite data, scientists can put together maps of sea ice extent for each month in each year. Scientists have been doing this since 1979.
Scientists make maps like those in the bottom right. In the maps: white is ice, brown is land, and blue is ocean.
So we can look at the total amount of September sea ice each year from 1979 to 2016 to get an idea of what kinds of changes have happened in the amount of Summer Sea Ice in the Arctic. The dotted blue line shows the sea ice extent in 1979 as a reference.
Why do we care about Summer Sea Ice? Click here to learn more.
So let’s see what the data demonstrates…
5) Overall, what has happened to the extent of Arctic summer sea ice since 1979?
Watch the data of Arctic sea ice extent in the graph. What do you notice about the amount of sea ice?
Now, watch it again and look at the map too.
What do you notice about where the extent of sea ice has changed? (Hint – pink is areas that lost ice compared to 1979, and green is areas that gained ice compared to 1979.)
OK, so it is changing. But how much sea ice are we talking about anyway?
6) How much sea ice are we really talking about?
So there is a lot of sea ice in the Arctic. And we know that the amount of sea ice has been changing over time. But how much sea ice is that really?
In the map, the amount of change in sea ice extent per year compared to 1979 (pink is loss and green is gain) is shown as the area of US States. What do you think?
That is a lot of sea ice, but that is only the surface area that it takes up. What about the thickness, is that changing too?
7) Reading sea ice volume data
As we know, scientists have been tracking the extent of Arctic sea ice (how far out in all directions the sea ice reaches) since 1979.
However, scientists use a combination of various measurements (satellites, buoys, field measurements, and submarine data) to analyze the thickness of sea ice in the Arctic.
When sea ice extent (a two-dimensional measurement) is combined with sea ice thickness, scientists can calculate the volume of Arctic sea ice (a three-dimensional measurement).
We can look at the thickness of sea ice each year from 1979 to 2016 to get an idea of what kinds of changes have happened in the amount of sea ice in the Arctic.
So let’s see what the data demonstrates…
8) Let’s compare sea ice extent to volume over time!
We now know that the location of sea ice (extent) has changed over time. But has the overall volume of sea ice changed over time too? Has it changed in similar ways?
Watch the data of Arctic sea ice volume in the graph. What do you notice about the overall volume of sea ice?
Now, watch it again and look at the sea ice extent graph too. What do you notice about how the amount of sea ice overall has changed?
OK, so sea ice volume is changing too. How much of a difference in the thickness would lead to such changes on overall volume are we talking about?
9) How much sea ice are we really talking about?
So there is a lot of sea ice in the Arctic. And we know that the volume of sea ice has been changing over time. But how much of a difference in sea ice thickness could that look like?
In this map, we are looking at the side view of the 48 contiguous United States. In 1979, the sea ice in the Arctic would have covered a flat U.S. around 7 feet high (think of a tall basketball player). Look at how the volume of sea ice per year has changed each year since then. What do you think?
That is a lot of sea ice that has changed since 1979! What does that mean for animals that use the sea ice as habitat?
10) What about the polar bears habitat?
This is a map of sea ice extent overall. The pink areas are where we have lost sea ice compared to 1979, and the green areas are where we have gained sea ice compared to 1979.
This map only compares two years – one at the beginning of the observational record (1979) and one near the present day (2016). However, how much variability in the location of sea ice happens between years (1979 through 2016)? Look back at slide 5 to see. What could variability from year to year mean for animals adapting to changes in sea ice overall?
Knowing that Polar bears rely on sea ice to reach their prey (seals). Where in the Arctic do you think polar bears have been most impacted by the changes in sea ice? (Hint – look for areas that used to have ice, but now do not.)
So overall, how are polar bears doing in terms of the amount of habitat they have? Has it changed over time?
But polar bears are not the only living things up in the Arctic…how are other living things doing with these changes in sea ice?
11) What about ocean plants?
Phytoplankton, microscopic plants in the water, grow under sea ice and in open ocean water. Phytoplankton provides the base of the Arctic food web.
We know that plants need: sunlight, water, and nutrients to grow. So with the sea ice thinning and covering less of the ocean water what do you think that means for the growth of these tiny ocean plants?
These are two images of phytoplankton blooms. When so many plants grow, they can change the color of the water as observed by satellites.
Do you think the growth of phytoplankton has changed over time? Do you think this is a good or bad thing if the amount of ocean plants changes?
How could scientists better understand if these changes in plants are good or bad for the Arctic community? What other Arctic animals might be impacted by changes in phytoplankton growth? (Hint: Think about the Arctic food web)
12) So what does this all mean for the Arctic ecosystem?
Look again through all of the data that we have been exploring. Are there overall patterns among the different variables? Do you think they are related to one another?
When using all of these data together, what conclusions can we make about what has been happening in the Arctic over time?
Interested in seeing how scientists think about how to talk to others about this? Explore the process of a message box!
To learn more about other things that are related to changes in sea ice (drivers), check out here.
Dr. Matt Druckenmiller (Science Advisor)
Kristin Hunter-Thomson (Story Design)
Lucas Marxen (Interface Development)
Dan Farnsworth (Data Visualization & Website Development)