Environmental Research Projects
A R Gillespie
I propose to use the STE research gift to date vanished glaciers that left rocky debris on the landscape of Central Asia. The cost per analysis is about $400, so we can get 25 dates which is enough to piece together one or two research papers, including one on some new discoveries made under National Geographic Support this summer. The discovery was a surprise, and NGS funding did not include provision for the dating.
a) What are we trying to do?
Glaciers advance and retreat in response to climate changes. From the elevation of deposits from long-vanished glaciers it is possible to make some quantitative estimates on the characteristics (temperature, precipitation) of ancient climates. By looking at sequences of deposits, it is possible to track how climate changed over time in the natural environment, before man changed things. I call this the natural baseline for climate change, because it is the long-term standard against which short-term modern changes must be assessed. But to make sense of the record, the ages of the different glaciations must be determined. We are doing this by analysis of exotic nuclides such as 10Be produced by the bombardment of rocks by cosmic rays. This occurs only when rocks are exposed on the surface – e.g., only after glaciers quarried the rocks and deposited them. We have collected rocks for dating on previous field trips, but currently have insufficient funds to date them.
b) Why Central Asia?
Most studies of past climate make use of mathematical models that “predict” climate at any time in the past. These models currently give inconsistent results for times more than 15,000 years ago. This period includes the ice age. To the extent the models have been checked by “ground control,” this has occurred in Europe, North America, and the Andes. All of the areas are close to the ocean – to one extent or another, they are maritime. Central Asia is in the center of Asia, as far from the ocean as possible. The climate is extremely “continental” – cold winters, hot summers, low precipitation. How do the mathematical models work here? Just because they work in moderate, relatively humid climates is no guarantee that they work everywhere, and they need to if they are to be used to study climate change. They have been little tested, and one use of our study is to work with Prof. Summer Rupper at Brigham Young University to do just that.
c) What will we learn?
Currently we expect to produce maps showing the fluctuation of the arid core (<200 mm/ yr precipitation) of Asia over time. We also expect to use these maps and data to estimate temperature fields for Asia in the past. Disagreement or agreement between our findings and results from climate models will act to test the ability of the models to make predictions or forecasts.
Our work is unlikely to “solve” the problem of climate change, but we expect to make important contributions to understanding the Earth system that will move us in the right direction.
d) Why look to the past?
The climate of the natural Earth has fluctuated wildly over the past millions of years. The effects of human endeavors are impressed on this record and can only be viewed against this backdrop. We seek to know how the natural system can behave in order to assess the impact of our industry and pollution. If we don’t know the causes of change, how can we plot an intelligent course to put things right?
Currently, self-styled climate “contrarians” argue that the Earth experienced truly extreme climates millions or even hundreds of millions of years ago, so we can’t prove we have had any impact today, and therefore we have no responsibility to curb our excesses. The record we are planning to study extends back one full glacial cycle, or to about 130,000 years ago. This is the current background of climate change on earth, not conditions that predated the evolution of mammals!
We have discovered that the mountains of the Gobi Desert experienced glaciations in the recent geological past. The Gobi lies in the middle of previous studies, and conditions there during the ice ages are poorly known. Dating the age of the glacial deposits in these mountains – the Gobi Altai – and in the surrounding ranges will be a big first step in understanding what this arid core of Asia was like during the Pleistocene.
Field work in northern Mongolia – what you do when all else fails and you are stuck in the mud!
A R Gillespie
We have been working for the past 17 years towards an improved understanding of the paleoclimate of Central Asia, using as an investigative tool the distribution of deposits from long-vanished glaciers as well as modern ones. The time frame of our study covers the past 130,000 years - essentially the last major glacial cycle. We have worked from Kyrgyzstan to Mongolia, and Tibet to Siberia.
Glaciers advance and retreat in response to climate. Even after they have vanished, the deposits they leave behind mark the extent of the coverage of the land, and from these deposits something about the climate conditions long ago can be estimated. We will be using Save the Earth funds in order to determine the dates of some of these past climate events.
Why does it matter? Climate change occurs in response to natural forces, but also in response to some of mankind's activities, but all we can observe is the resultant of changes from both sources. If we are ever to address some of the climate problems we are facing, it is necessary to understand the causes. What we are doing in Central Asia helps establish how the natural climate system behaved before there was any question of anthropogenic forcing.
Why Central Asia? Central Asia has a continental climate, with low precipitation, high summer temperatures, and low winter temperatures. It is an extreme "endmember" for climate in the temperate latitudes where most people live. Studying paleoclimate in Central Asia helps define the limits within which the Earth system has functioned in the recent geological past. Central Asia is also more sensitive that many places to climate change, because many people there are living "on the edge" - in a marginal environment where small changes have large effects in the daily lives.
What are we doing specifically? With this research effort, we will try to establish the ages of glacial deposits in the heights of the Gov'i -Altai, a mountain range in the middle of the Gobi Desert. It has previously thought to have been unglaciated during the Pleistocene, but our studies have shown the presence of extensive ice caps there. When we know the ages of these glacier advances, we will be able to flesh out the climate maps of Asia, maps in which the Gobi is essentially uncharted terrain in terms of paleoclimate.
Save the Earth Foundation