American Museum of Natural History

Climate Change: Course Preview

Uncertainty, Risk, and the Future

This discussion was selected from Week 6 of the AMNH online course Climate Change, part of Seminars on Science, a program of online graduate-level professional development courses for K-12 educators. This is an excerpt from an actual course discussion, but learner names have been changed. Explore more sample resources...

The focus this week is on energy balance, and how atmospheric and ocean circulation relate to the climate system. This figure (download the PDF) represents the Earth's global annual mean energy budget (in Watts per square meter, W/m2) for the period between March 2000 and May 2004. The broad arrows indicate the schematic flow of energy in proportion to their amounts.

Using this figure and examples from this week's reading, discuss some of the factors that contribute to balance within the climate system. How does the climate system maintain balance on different scales? How do the different components interact? What are some potential paths that energy can take? What questions do you have about this diagram or the way the system works?

Download the PDF: Global Energy Flow

Mike 18 Mar 2:37 PM

The word "uncertainty" is appearing in many of reading assignments and I think that even though we have a fairly good understanding, in general, of how many of the processes within the climate system work there can still be uncertainties associated with the specifics within the processes and especially when these processes interrelate with other processes. Unfortunately, when scientists express these uncertainties there are segments within society that use that as an excuse to throw the entire baby out with the bath water - to deny climate change - and to "believe" whatever they want to believe. Evolution has "uncertainties" too, and as Dr. Neil DeGrasse Tyson said few weeks back on the Bill Maher show when commenting about evolution - the great thing about science is, it doesn't really matter whether you believe in it or not, it's still true. When it comes to the readings this week, and the global energy chart, I realize that there are uncertainties within the existing processes involving the climate system. I think (hope?) further scientific study will help us to better understand some of these uncertainties. However, I wonder if there are major processes within the climate system that we have yet to uncover. Much of the understanding we have of the processes discussed in the readings has only occurred in the last few decades.

Student Victor 18 Mar 2:45 PM

I like uncertainties (in fact, my first lab class is called "errors are your friends"). However, I am not quite sure whether 'major [new] processes' can be attributed as the source of uncertainties, though for that we must know how large the uncertainties are and what we mean by 'major'. If there are anomalies in the data, now that is a fruitful place to look for new processes (examples galore in the science).

It is interesting to compare the notion of uncertainties which can be attributed to experimental noise (apparatus) and which are model dependent (this was always interesting doing early universe cosmology).

Student Frank 19 Mar 9:05 AM

Uncertainty drives technology. I agree that uncertainties are not necessarily bad. Technology is driven by it, so is the scientific method. Uncertainties force the scientist to look deeper, to explore further, to refine his/her question, and most of all, challenge conclusions we come to.

As Mike mentioned, a lot of this science is young, new, and we're still looking for answers. So much good science lies within our uncertainties, but a lot of positives come from looking into and identifying where the uncertainty comes from, its source. In Earth Systems Science, there are a lot of variables in play, it would be difficult, almost unscientific to ignore the value of uncertainty. Science makes statements based on data, so our instrumentation and interpretation cannot be perfect.

Thanks for mentioning this further Mike and Victor.

Instructor Susan 20 Mar 10:06 AM

As you can tell by diving only this far into the course, this is an enormously complicated subject. While scientists have studied the carbon cycle and used models to make solid predictions, you're right Frank, the "interpretation cannot be perfect," because we just can't tell to the molecule how much CO2 the phytoplankton will absorb, how much will be released when zooplankton build their shells, how much the ocean will release in upwelling, etc etc etc. Especially when we take this out over an extended period of time (but I'm giving away our Week 3-4 assignment)

Student Sarah 23 Mar 7:22 PM

Temporal Scales and Climate Change

I hope I'm not delving too much into week 3-4 (which I haven't really looked at yet), but what you said, Susan, reminded me of a discussion in our Earth: Inside and Out course.

During Week 2 or so, we looked at radioactive dating by carbon, uranium, and other isotopes. In the case of uranium, especially, we can date back millions of years. However, the further we go back in time, the more the standard of error increases, so they we may be 'off' by 1 year, then 10, then 100... but it doesn't seem to matter because we're not tracing the precise genealogy of a dinosaur.

I think that climate change predictions should be the same way: we're not making weather forecasts for the year 2300--we're trying to get a rough estimate that will help us better understand today and apply politics, management efforts, and current technologies to existing problems. It's too bad the media doesn't see it this way!

Scientist Mark 20 Mar 11:13 AM

I'd like to point out that we are discussing details when we discuss the complexity of the system. Most of the fundamental science involved in global warming (greenhouse gases) has been around for over 150 years, solid measurements of CO2 in the atmosphere have existed for over 50 years - and show the levels to have increased beyond the levels of the past 1 million years, and even climate models have been around, making essentially the same general projections, for over 30 years. The basics are hardly new. Details are always added, thus there is always something new.

Student Rachel 20 Mar 1:06 PM

I agree that being aware of uncertainties in data is an integral part of the scientific process but what is important is being aware of whether the uncertainties are large enough to affect the conclusions we draw from patterns in the data. This aspect of dealing with experimental data is part of the assessment in the IB science courses and students must refer to uncertainties in the results and conclusion sections of their experiment reports. I also think that what Mike says is true in that having uncertainties in data is often seen by non-scientists as an indication that the data is not reliable.

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