Questions about Global Climate Change

During September and October of 2005 Catherine Yansa, a Biogeographer and Assistant Professor of Geography at Michigan State University, answered questions about Global Climate change. Learn more about Catherine Yansa's research.

Your Comments, Thoughts, Questions, Ideas

Liza's picture
Liza says:

What's the most rewarding aspect of your work?

posted on Thu, 06/23/2005 - 11:03am
Catherine Yansa's picture
Catherine Yansa says:

I enjoy working with plant fossils even while doing the more "boring" part of data collection. But what I like most is fitting the pieces of data together into a puzzle - that of reconstructing past environments. You can do this after you plot the data and see any interesting patterns and use your knowledge of ecology and geology to explain them. I also enjoy presenting my results at conferences, which also gives me a chance to visit interesting places and to get caught up with colleagues, some of which have become friends over the years.

posted on Wed, 07/27/2005 - 2:19pm
Liza's picture
Liza says:

How did you get interested in biogeography and climate change?

posted on Thu, 06/23/2005 - 11:03am
Catherine Yansa's picture
Catherine Yansa says:

I became interested in biogeography and climate change when I was an archaeologist. While I was investigating Paleoindian sites on the northern Great Plains I wondered what the environment was like during the time of the Paleoindians. I approached a geologist about doing a Master's project with him and got into plant fossil research at that point and have loved it ever since. I learned about biogeography and climate change by completing a Ph.D. in geography. Biogeography offers a holistic way of studying changing vegetation patterns over time and different geographic areas. I've always been interested in plants; I enjoy gardening and horticulture, so it was good fit. My work has led me to collaborate with other scientists (geologists and archaeologists, primarily) who study related things so we "work up" cores together and pull this together into scientific papers published in journals. My work also brings me to conferences to present my results and allows me a chance to visit with friends and colleagues who live elsewhere. These conferences also offer field trips, so I sometimes tour the geology and ecology of places, like Yellowstone National Park, with the experts that work there. There are also international conferences and I'm starting to participate in those, which are much fun. So you see, life as a scientist is not as dull as most people think :)

posted on Wed, 06/29/2005 - 2:08pm
Liza's picture
Liza says:

What did you study in high school and college? If I wanted to do what you do, what should I study?

posted on Thu, 06/23/2005 - 11:03am
Catherine Yansa's picture
Catherine Yansa says:

Very cool that you want to do what I do. Paleoecology/paleoenvironment reconstruction is a growing field, despite not many people knowing about it. I fell into this field by accident, which is the way that most of my colleagues have done too. My high school training was general though I have several courses in biology and history. I have a B.A. Honors degree in Anthropology (I was an archaeologist for awhile), a Masters of Science degree in Geology and a Ph.D. in Geography at the University of Wisconsin-Madison. If you want to study plant fossils you need a good background in plant biology (botany), including plant taxonomy (Latin naming of plants and the characteristics of different plant familes), plant ecology, geology and physical geography (to understand how landscapes change, sediments and fossils are deposited in lakes, etc.), and climatology (especially about global warming). If you have further questions, please contact me. Good luck!

posted on Wed, 06/29/2005 - 1:56pm
Liza's picture
Liza says:

What kinds of tools do you use in your work?

posted on Thu, 06/23/2005 - 11:04am
Catherine Yansa's picture
Catherine Yansa says:

To collect the fossils I must first collect mud from the bottoms of lakes, since the fossils buried in the mud have accumulated for thousands of years, ever since the lakes formed with the melting of glaciers. To get this I use coring equipment - a metal hollow cylinder attached to rods, which I purchased from Dr. Herb Wright of the Univ. of Minnesota. Coring is easiest in winter when one can drill a hole through the ice so people can freely move around and you can set up all of your other equipment. In the tropics, people do this from a raft (which can tip!). For coring on ice you need at least 4 people. Once colleagues and I set up the equipment we push the corer down 1 m (~3 feet), the length of the devise, and pull it up to the surface. We then wrap each section in plastic wrap and store them in PVC tubes cut in 1/2 length-wise. We make sure to label on these mud "sausages" the depth from which they were collected. We keep going down the same hole until we can penetrate no deeper, which usually means that we have reached the glacial till and have collected all of the mud since the lake basin formed after the retreat of the glaciers.

Back in the lab I take small (about the size of a sugar cube) samples of mud for pollen analysis, which involves a long and complicated procedure I won't discuss here since this exhibit pertains just to seeds. For the seed (macrofossil) analysis I take larger samples (usually about 50 cubic centimeters, about the size of a closed fist) and place them in a sieve with a fine mesh and wash under tap water. This "cleans" the sample, removes the fine mud particles and concentrates the fossils. I store these into beakers with water and make sure they are each labeled with the site and depth from the sample came from (deeper samples are older). I then pour a little of this soupy mixture into a petri dish and look under a low-powered microscope which has 20-40 X magnification. I pick out the seeds and other plant remains and store them in labeled glass vials. Some of these I select for radiocarbon dating, which I sent to a radiocarbon dating lab and a month or more later receive the dates and use this for plotting the data. Based on the species I identify and the numbers of seeds of each I count I can then interpret what the vegetation was like in the past. I'm able to do this since I have an understanding of how many seeds these same species produce today and in what environments these species currently live. I usually do pollen analysis at the same time which helps me understand what plants were living in the area, since some species are better represented as fossils in the form of pollen rather than seeds and visa versa.

posted on Wed, 06/29/2005 - 1:48pm
Anonymous's picture
Anonymous says:

How many years until Antartica will melt?

posted on Thu, 06/23/2005 - 2:12pm
Catherine Yansa's picture
Catherine Yansa says:

Definitely the ice sheets are already melting. But I'm not sure of the rate of melting, since I do not do any research in Antartica. I suggest that you check out the websites of NOAA (National Oceanic and Atmospheric Administration) and the United States Geological Survey.

posted on Wed, 07/27/2005 - 2:14pm
From the Museum Floor's picture

When or how do plants make food for themselves?

posted on Fri, 06/24/2005 - 10:44am
Catherine Yansa's picture
Catherine Yansa says:

Plants don't make food for themselves--they extract main base cations (calcium, phosphate and other nutrients found in "fertilizers") from soils and draw up water through their roots. Some plants have a mutually benefitting arrangement with fungi attached to their roots; these fungi fix nitrogen (take it from the air and put it into the soil) which the plant roots then uptake for plant growth. Plants make seeds that can be eaten by animals, including humans.

posted on Wed, 06/29/2005 - 1:19pm
Anonymous's picture
Anonymous says:

How different is North Dakota's climate today compared to 9000 yrs ago? Has its location changed?

posted on Sat, 06/25/2005 - 11:21am
bryan kennedy's picture
bryan kennedy says:

Interesting question with a surprising answer. About 11,000 to 13,000 years ago North Dakota was just coming out of being glaciated and looked and felt much like the tundra does today. When the glaciers left about 10 to 11,000 years ago it began to get warmer and drier until about 7,000 years ago when it started to reverse and get a little wetter and cooler. What that all means is that 9,000 years ago North Dakota was just about like it is today, at least as far as the climate goes, but it has change a lot in between.

posted on Thu, 09/01/2005 - 1:51pm
From the Museum Floor's picture

How much would the atmosphere have to change to be unable to sustain life? And in how many different ways?

posted on Mon, 06/27/2005 - 9:58am
Catherine Yansa's picture
Catherine Yansa says:

Global temperatures would have to rise substantially more than we have predicted to occur (from global warming) to make the planet unable to sustain life. Trace gases, like carbon dioxide, are responsible for the greenhouse effect and these are rare in our atmosphere (<5%) and hence provide an upper limit for global warming.

posted on Wed, 06/29/2005 - 1:06pm
Anonymous's picture
Anonymous says:

Will the Earth eventually end up like Mars?

posted on Mon, 06/27/2005 - 12:19pm
Catherine Yansa's picture
Catherine Yansa says:

I'm not an expert in astronomy, but based on what I know about the Earth's history I doubt that Earth will eventually end up like Mars. The Earth has a completely different atmosphere than Mars for starters. The heating capacity of our atmosphere is based on trace gases - carbon dioxide, methane and water vapor - which absorb long-wave (thermal infrared radiation) and heat our atmosphere. These trace gases only make up ~1-5% of the atmospheric gases, the rest mainly composed of nitrogen and oxygen which don't affect the heating of the atmosphere. So this means that there's an upper limit for how warm the atmosphere can get. At the time of the dinosaurs we estimate from fossils, etc. that the atmosphere was ~10 degrees F warmer than present globally, meaning that some places warmed more and others less, but on average about this amount.

posted on Wed, 06/29/2005 - 1:02pm
andrew's picture
andrew says:

What was your favorite subject in school?

posted on Mon, 06/27/2005 - 12:50pm
Catherine Yansa's picture
Catherine Yansa says:

My favorite subjects were history and biology and now I study both.

posted on Wed, 06/29/2005 - 12:56pm
Anonymous's picture
Anonymous says:

Is there any consensus on how much of climate change is due to humans activity and how much is due to normal nature like volcanoes? Some people say all global warming is natural...and some say it's all our fault!

posted on Tue, 06/28/2005 - 4:47pm
Catherine Yansa's picture
Catherine Yansa says:

Global warming can be natural. For instance, at the time of the dinosaurs (which went extinct 65 million years ago) it was estimated from fossils and other data that it was 6 degrees Celsius (10 deg. F) warmer than present. But over the last 2 million years we have been going through glaciations (when ice covered Minnesota) and interglaciations (like today) and it has been overall cooler than at the time of the dinosaurs. The peak warmth of our interglaciation, which started 10,000 years ago was from 9,000 to 6000 years ago and we have been on a cooling trend ever since. Superimposed on this cooling trend is global warming, which 98% of climatologists think is caused by humans. Without out a doubt there has been an increase in CO2, one of the greenhouse gases. There's only a few climatologists out there (about 2%) that think it's completely natural. These data come from the Intergovernment Panel on Climate Change, which is composed of over 100 atmospheric scientists that meet every ~5 years and produce huge reports. Thanks for your interest.

posted on Wed, 06/29/2005 - 12:50pm
Lineasha's picture
Lineasha says:

How do you feel about skeptics that say that global warming does not exist? Ex. Glaciers have been retreating for years previous to the increase of co2 levels,etc.

posted on Tue, 07/05/2005 - 3:03pm
bryan kennedy's picture
bryan kennedy says:

There will always be skeptics on any issue. For example, some people still believe that the Earth is flat or that the sun revolves around the Earth. I feel that we should not wait to try and convince all the skeptics. The important point is that almost all of the worlds scientists and the vast majority of the worlds governments understand and agree that global warming is real. The evidence is overwhelming and not just confined to melting glaciers. The average temperature of the earth is going up, the permafrost is melting, the oceans are warming up, the oceans are rising because of the melting ice caps on land, and the climate is changing among many other things. All of these are measurable and they have changed or increased in an alarming way during the last 100 years, and most rapidly during the last couple of decades. It is not prudent to wait and fix sometime until it is broke because it may not be fixable.

posted on Thu, 09/01/2005 - 1:52pm
Anonymous's picture
Anonymous says:

what problems do you forsee if we dont take action against global warming?\r\n\r\n

posted on Thu, 07/07/2005 - 12:53pm
bryan kennedy's picture
bryan kennedy says:

There are many potential problems. Some are a little more frightening than others, but almost all consequences of global warming are negative from an ecological perspective. Some of the most troubling from a human perspective are the creation of large scale droughts with crop failures and large scale famines, the warming of the oceans and the death of reefs and fisheries that the world population depends on for food, the melting of large ice caps in places like Greenland or Antarctica which will raise the ocean levels more than twenty feet and flood cities that are homes to hundreds of millions of people. Global warming has the potential to change ocean currents that are important to life in the sea and climates on land, it will cause the extinction of an unknown number of plant and animal species, it will make it to hot to live in some areas, melt sea ice important to birds, polar bears, whales and certain human populations like Eskimos. Many rivers depend on snow melt from mountain tops for water in the summer, and they could stop flowing if it doesn't snow or if the snow all melts at once. It will melt the permafrost in the tundra and allow the decay of vast amounts peat. That and the death of forests around the globe will create fire conditions and fires that will burn to release more carbon dioxide into the air. These are but a few of the consequences of global warming, and new scientific information points out that these changes could occur very rapidly once they get started. These facts are particularly important when you understand that we are already seeing some of these changes happening right now. There is a huge pool of scientific data that all points to the fact that global warming is happening and it is being driven by human activity. All in all it is not a good thing, and we should not take chances like that with the planet.

posted on Thu, 09/01/2005 - 1:52pm
Cathy's picture
Cathy says:

What type of education do you need to work in this field? How many people are working in this field today?

posted on Thu, 07/07/2005 - 2:25pm
bryan kennedy's picture

Hey Cathy,

Catherine answered a question a while ago about her schooling, that might tell you what you are curious about. Catherine, feel free to fill in more information if you have other thoughts.

posted on Thu, 07/07/2005 - 3:47pm
Anonymous's picture
Anonymous says:

IS IT TRUE THAT POLAR BEARS WILL DIE IF GLOBAL WARMING CONTINUES? \r\n

posted on Thu, 07/07/2005 - 8:34pm
Liza's picture
Liza says:

Polar bears are definitely having a rough go of it. Check out this page, and then do a search of the Internet on your own for more information.

posted on Sun, 11/13/2005 - 4:10pm
Luke Long's picture
Luke Long says:

Is the theory about the glaciers moving through North America just a theory or is there scientific proof that the glaciers are the cause of our flatlands?

posted on Wed, 07/13/2005 - 11:29am
bryan kennedy's picture
bryan kennedy says:

Good question. To begin with, a scientific theory is not what many people think of when they hear the word theory. Since there is no one living today that saw or documented the glaciers that once covered this area we only have indirect evidence that they were here, so it remains a scientific theory. Other things, like gravity, remain a theory even though we can observe them because, even though we can see it, we don't know exactly how it works. Most importantly, scientific theories must be testable and those concerning the continental glaciers certainly are testable. We have huge amounts of evidence that glaciers covered much of North America with up to more than a mile of thick sheet of ice up until about 10,000 years ago. Those glaciers left behind many features and signs and they created not only flatlands but many highlands as well. One of the best ways to check this out is to look at some aerial photographs of the region or go to a book that describes how our landscape was formed. I recommend that people read the book Minnesota's Geology by Richard Ojakangas and Charles Matsch for a good description of the evidence for glaciers in Minnesota and the upper mid-west. All around us are hills called moraines that were left when the gravel and sand laden ice melted. There are long sinuous hills called eskers formed by the gravel in stream beds that flowed across the ice sheets. There are other kinds of glacial hills called drumlins and kames. We see many of these same types of features where modern glaciers are melting and retreating today. We also see large river valleys and large flat outwash plains where rivers flowed as the glaciers melted. We see large grooves and scratches where the glaciers moved over the bedrock. We find large boulders and gravel carried here by the glaciers from bedrock only found far to the North or East. Many of our lakes are formed by large blocks of ice that were once buried in the gravel that have now melted to leave a depression called a "kettle lake". We can also measure the age of our lakes in their sediments and they are all about 10,000 years old, formed after the glaciers left. We can even measure that the land is still rising after the weight of the glaciers disappeared 10,000 years ago. We have this and much more in evidence for glaciers.

posted on Thu, 09/01/2005 - 1:53pm
Norcorafatimah's picture
Norcorafatimah says:

How is global climate change affecting glaciers?\r\n

posted on Wed, 07/20/2005 - 3:27pm
Liza's picture
Liza says:

British researchers did a survey of glaciers in Antarctica. You can read about that in the story, "Beating a hasty, but glacial, retreat."

Scientists have been watching glaciers in Glacier National Park, too. See what they've found.

posted on Sun, 11/13/2005 - 3:20pm
Dale's picture
Dale says:

Good day to you.\r\nIf you could seperate the carbon atoms from the carbon dioxide before the gas is released into the atmosphere that would leave only oxygen and carbon correct? Then with after seperating the molecules to their elemental form and placed into a collector would this not help prevent the effects of this gas? I have a theory to seperate the atoms and contain them which would in turn eliminate the need for atmosephere scrubbers.\r\nThnak you for your time and good day to you.

posted on Wed, 07/20/2005 - 3:47pm
bryan kennedy's picture
bryan kennedy says:

Great observation and question! The separation of carbon dioxide into carbon and oxygen is already taking place on a global scale and it is the process that has kept carbon dioxide levels in check for hundreds of millions of years. Of course, what I am referring to is photosynthesis in plants. In sunlight, photosynthetic (mostly green) plants take carbon dioxide and with the help of chlorophyll and energy from the sunlight, turn it into carbon based sugar and oxygen. The plants then convert the sugar into wood (cellulose) and other plant compounds. Most people may not realize that the dry weight of wood comes almost entirely from the carbon dioxide in the air! Plants and plant remains are what scientists call a carbon "sink" or repository, keeping it out of the atmosphere. It gets turned back into carbon dioxide if the wood is burned (oxidized) or if it is naturally turned into coal or oil over millions of years and is once again burned like we do with oil and gas. We could devise another way to break apart carbon dioxide but that would take energy (more fuel) and we would never be able to do it as well or at the scale of all the plants in the world. One answer would be to protect as much plant life as we could so that plants continue to do the job for us.

posted on Thu, 09/01/2005 - 1:52pm
Anonymous's picture
Anonymous says:

Dear Catherine,
I have a penpal in Brazil with whom I would like to start an identical garden so that we can compare growth rates of our plants. I'm wondering what sort of plants we would be able to grow that would thrive and survive in both the climate of Minnesota and Brazil. Thanks! lisa

posted on Thu, 08/04/2005 - 6:29pm
Anonymous's picture
Anonymous says:

What is yourfavorite region to study?

posted on Wed, 08/10/2005 - 2:54pm
bryan kennedy's picture
bryan kennedy says:

Thanks for asking. I like the upper midwest and Great Lakes States because of the tens of thousands of lakes and great differences in climate and vegetation across the region. For example, pre-European settlement habitats in Minnesota go from open prairie in the Southwest and West to boreal (coniferous/pine) forests in the Northeast. This change from prairie to deciduous trees, to pine and spruce forests happens over a very short distance. In some areas it's only a matter of miles. This makes it a great place to study past climate changes and the way forest and prairie borders moved in response top climate. It is also a good place to study modern climate change because it is one of the regions where we are most likely to see the vegetation change as the climate warms.

posted on Thu, 09/01/2005 - 1:51pm
Anonymous's picture
Anonymous says:

please give me this answer as quickly as possible becasue i need it tommorow (11-14-04): \r\n\r\nwhat are positive effects of global warming?

posted on Sun, 11/13/2005 - 1:16pm
Liza's picture
Liza says:

We posted a story on this topic a while ago. ("Who's afraid of a little global warming?") You can find it by typing "global warming" into the search bar, or following this link.

posted on Sun, 11/13/2005 - 2:50pm