Arctic ice thickness decreasing - English Grammar

A recent study based on satellite radar altimetry indicates drastic thinning of Arctic ice during the winter of 2007. It was found that the ice thickness had been fairly constant for the five previous winters. The researchers ⁽¹⁾to be able to
Note the use of “to be able to” to replace the modal verb “can”. Here, also “could” is possible. "Can" is a commonly used modal verb. It can be used to express ability or opportunity, to request or offer permission, and to show possibility or impossibility.were able to⁽¹⁾ highlight widespread ice thinning in areas covered by both old and young ice. This thinning constitutes the most severe since records started being taken in the early 1990s.

The study by scientists of University College London has been published in the journal Geophysical Research Letters. The work provides the first definitive ⁽²⁾proof
Note that the verb form to the noun “proof” is “to prove”.proof⁽²⁾ for overall decrease in Arctic ice volume, claim the authors.

The researchers have found that last winter's ice thickness represented a decrease of an average of 26 centimeters below the 2002-2008 winter average. The greatest decline of 49 centimeters was in the western Arctic, which could explain the region's becoming relatively ice-free this summer, allowing it to be open to shipping for the first time in 30 years. The record low of ice thickness ⁽³⁾during
"During" is used with a noun/pronoun; “while” is used with a subject and a verb.during⁽³⁾ summer happened when the weather was not abnormally warm.

Katharine Giles, the lead author, points out that the study used satellite data sets, which had a number of advantages over other methods. Previous studies ⁽⁴⁾have used
Here the “Present Perfect Simple” is used. It is often used when the time is recent and when there is duration from the past until now.have used⁽⁴⁾ measurements from drilling, or submarine and airborne surveys. These studies could be severely limited by time and space. The present study utilized continuous, all-weather, day-and-night radar altimeter data from the European Space Agency's Envisat satellite. The study measured ice thickness from October to March, 2007, over more than half of the Arctic.

There ⁽⁵⁾has been
Another good example of the use of the “Present Perfect Simple”.has been⁽⁵⁾ considerable uncertainty over the causes of ice loss in the Arctic. It has been debated that ice could have been piled up against the coast, thus reducing the sea ice extent. Measurements of the ice thickness, as in the present study, give definite proof for ice melting. "So this means melting; it doesn't mean that the ice has just been pushed up against the coastline," remarks Seymour Laxon, co-author of the paper.

The conclusions of the study can help predict what could happen with the ice cover in future. Deflection of sunlight by the Arctic ice cap could be reduced, leading to larger areas of water, which can absorb heat. Warmer temperatures will in turn promote more ice melting. "About five years ago, the average projection for the sea ice disappearing was about 2080", said Dr Laxon. "But the ice minimums, and this evidence of melting, suggests that we should ⁽⁶⁾favor
Note that “favor” is American English and “favour” is British English.favor⁽⁶⁾ the models that suggest the sea ice will disappear by 2030-2040, but there is still a lot of uncertainty."