Study Finds Humans Tilted Earth By A Shocking 31.5 Inches Contributing To Climate Change

Scientists are constantly on the lookout for ways to slow down climate change, such as one study that devised a $200 trillion diamond dust umbrella for Earth. They are also seeking all the possible contributors to climate change, which even includes belching cows (seriously). Now, a new study finds humans tilted the Earth by a shocking 31.5-inches in less than two decades, and in turn, contributed to climate change.

According to climate models, scientists estimate humans pumped 2,150 gigatons of groundwater, which is equivalent to more than 6 millimeters (0.24-inches) of sea level rise, from 1993 to 2010. While .24-inches of sea level rise may sound like an extremely small amount, it may actually have a fairly large impact on Earth’s climate.

In a statement, Ki-Weon Seo, a geophysicist at Seoul National University, and lead on the new study, remarked, “Earth’s rotational pole actually changes a lot. Our study shows that among climate related causes, the redistribution of groundwater actually has the largest impact on the draft of the rotational pole.”

The Earth’s rotational pole is the point around which the planet rotates. It moves when the position of the Earth’s rotational pole varies relative to the crust, during a process called polar motion. Just as adding small amounts of weight to a spinning top, the Earth will spin a little differently as water is redistributed.

The researchers modeled the observed changes in the drift of Earth’s rotational pole and the movement of water. First, with only ice sheets and glaciers being considered, and then later adding in different scenarios of groundwater redistribution.

In the study, the authors list two key points: Earth’s pole has drifted toward 64.16 degrees East at a speed of 4.36cm/yr during 1993-2010 due to groundwater depletion and resulting sea level rise. Including groundwater depletion effects, the estimated drift of Earth’s rotational pole agrees remarkably well with observations.

"This is a nice contribution and an important documentation for sure," remarked Surendra Adhikari, a research scientist at the Jet Propulsion Laboratory who was not involved in this study. "They've quantified the role of groundwater pumping on polar motion, and it's pretty significant."

Another key aspect of the study is it found the location of groundwater matters for how much it may change polar drift. It found redistributing water from the midlatitudes has a larger impact on the rotational pole. During the study, most water was redistributed in western North America and northwestern India, both located in the midlatitudes.

Seo noted that the redistribution of water in these areas could theoretically alter the change in drift, but only if the scenarios are sustained for decades.

According to Adhikari, the rotational pole normally changes by several meters within a year or so. So, changes due to groundwater pumping do not run the risk of changing seasons. However, on geological time scales, polar drift can have an impact on climate.

The researchers say the next step in studying the effects of groundwater redistribution on climate change could come from the past. Seo explained, “Polar motion data are available from as early as the late 19th century. So, we can potentially use those data to understand continental water storage variations during the last 100 years."