Falling Ice and Rising Seas
2025
The relationship between water and gravity is one of nearly infinite complex relationships embedded in our world. It is not enough to wrestle with the scales of these problems. We must also confront their complexity and plan for the unpredictable flows of water, people, resources, and vulnerability that will follow the destabilization of the equilibrium we are creating/approaching.
The earth is not a perfect sphere. Officially it is an oblate spheroid, a slightly flattened sphere with a bulge around the equator. However this definition of its shape is also incomplete. In reality, the earth is an imperfect mass. Its land and water are distributed unevenly across the surface, creating what scientists call a 'geoid’. The changes in density and distribution translate to a varying effect of gravity across its surface, which exerts more pull around the highest density regions of the earth.
These fluctuations in the pull of gravity are revealed by the GRACE (Gravity Recovery and Climate Experiment) satellites. This program, a creation of NASA JPL, is one of the thousands of transparent and trustworthy data collection programs funded by taxpayer dollars and publicly released at no cost by the United States government. The binary pair, nicknamed Tom and Jerry, follow a polar orbit 305 miles above the earth. As they travel they precisely record their separation, with subtle drifts closer and further apart tracing the shifts of gravitational forces on the earth below.
Tracing these minute differences over time reveals that gravitational forces are moving, largely following the redistribution of water in a changing climate. 2.1% of the world's water, including 75% of the world's fresh water, is frozen in glaciers, largely concentrated in Antarctica and Greenland. However, these forces are more dynamically linked. These glaciers are so massive that they exert their own gravitational force, revealed by the travels of Tom and Jerry, drawing the liquid water of their surrounding oceans closer. As the glaciers melt they release frozen water and their gravitational force lessens causing vast amounts of water, much more than their frozen volumes, to flow in unpredictable ways.
This animation traces the dynamic readings of the mass balance of the Earth… where loss of ice and water on land (including groundwater) creates decreasing gravitational pulls, leading to the thickening or deepening of the ocean where gravity has increased between 2007 and 2017.
Project Team:
Joe Ferdinando
Alexander Kobald
J. Meejin Yoon