The change is less than a meter, but it's a neat way to confirm other estimates of how much groundwater is getting pumped out. From the article: Here is the study and the "plain language summary":
The change is less than a meter, but it's a neat way to confirm other estimates of how much groundwater is getting pumped out. From the article:
A 2016 study demonstrated that climate-driven changes in water mass distribution can cause Earth’s poles to drift. But the activities examined in that study didn’t perfectly explain the observed polar motion.
With observational data spanning 17 years, Seo and his colleagues used a computer model to simulate which hydrological sources significantly affected Earth’s tilt. To Seo’s surprise, modeled polar drift only matched the observations when groundwater pumping was included.
“We have a lot of dams, and there are a lot of reservoirs on land, so I originally thought that should be very important,” said Seo, “but actually it’s not. After including the groundwater effect, I finally could explain all [of the] observations.”
The shift in Earth’s tilt is far too small to impact weather or seasons, Seo said. However, the team of scientists discovered that polar drift can be used to estimate the effect of groundwater pumping on sea level rise.
When water is sucked from the ground to irrigate crops and meet global freshwater demands, it eventually travels through rivers and other pathways into the world’s oceans. From 1993 to 2010, the researchers found, groundwater pumping shifted enough mass to contribute to 0.24 inches in global sea level rise.
Here is the study and the "plain language summary":
Melting of polar ice sheets and mountain glaciers has been understood as a main cause of sea level rise associated with contemporary climate warming. It has been proposed that an important anthropogenic contribution is sea level rise due to groundwater depletion resulting from irrigation. A climate model estimate for the period 1993–2010 gives total groundwater depletion of 2,150 GTon, equivalent to global sea level rise of 6.24 mm. However, direct observational evidence supporting this estimate has been lacking. In this study, we show that the model estimate of water redistribution from aquifers to the oceans would result in a drift of Earth's rotational pole, about 78.48 cm toward 64.16°E. In combination with other well-understood sources of water redistribution, such as melting of polar ice sheets and mountain glaciers, good agreement with PM observations serves as an independent confirmation of the groundwater depletion model estimate.
The change is less than a meter, but it's a neat way to confirm other estimates of how much groundwater is getting pumped out. From the article:
Here is the study and the "plain language summary":