Science & evidence · News English
Following water with gravity
Satellite records reveal patterns in water stored on land.
Read the story, check the words, then answer the questions and speak.
A sharper picture of stored water
What can researchers gain, and lose, by combining many observations?
1Water stored on land is changing, and rainfall is only part of the explanation. In a report published on 20 October, NASA describes a study of satellite records from April 2002 to November 2025. The researchers examined how human activities relate to long-term changes in water storage.
2The GRACE and GRACE Follow-On missions measure small changes in Earth’s gravity. Water and ice affect mass, so these measurements help scientists estimate gains and losses. The instruments do not simply take photographs of underground water.
3By combining many satellite passes, the team produced maps with five to ten times more spatial detail than earlier analyses. However, this improvement came with less detail about when changes happened. The study identified 40 regions where water-storage changes also aligned with activities such as irrigation, reservoir filling and land-use change.
4Groundwater-irrigated farmland was strongly associated with falling storage in several regions. Elsewhere, reservoirs and water diversion contributed to gains. Our archive photograph shows the Karakum Canal in 2021, not the new study’s full dataset. The findings show why both climate and human choices matter. They also remind us that a clearer map does not automatically provide a clearer timeline.
Original teaching summary. Models and learning examples are illustrative, not news quotations.
Word help · Three useful words
Read the meanings and examples. Choose one word to use in your own sentence.
storage
the amount kept for later use
The reservoir increased local water storage.
irrigation
supplying water to land for growing crops
The farm uses irrigation in dry months.
tradeoff
a balance in which gaining one benefit means losing another
More detail can involve a tradeoff.
Check your reading · Three questions
Choose one answer for every question, then check. You can change an answer and check again.
Useful English
Although the map has more spatial detail, it has less time detail. The map is sharper, but the timeline is less precise. These are practice paraphrases, not quotations.
Speak for 20 seconds
Describe a tool or method with one benefit and one limitation. Use although or but.
Speak: your ideas
Describe a tool or method with one benefit and one limitation. Use although or but.
Labelled model answer
Model: Although a map shows many roads, it may not show a new closure. I would check another source before travelling.
Illustrative learning example, not a news quotation.
Alone: repeat without the model. Tutor: ask a follow-up question.
Mastery check · Three questions
Choose one answer for every question, then check. You can change an answer and check again.
Sources and reporting date
NASA Earth Observatory report dated 20 October 2026; original article:published_time is 2026-10-20T00:01:00-04:00. Study data cover April 2002 to November 2025.
- The Human Fingerprint on Earth’s Water Cycle
NASA Earth Observatory report dated 20 October 2026; original article:published_time is 2026-10-20T00:01:00-04:00. Study data cover April 2002 to November 2025. - Photograph source
Archive astronaut photograph, 13 June 2021: the Karakum Canal. Cropped and enhanced by NASA; not a new water-storage map.