[English Writing] Good references

Reference

In particular, his calculations suggest, the firn of the Wilkins, Larsen C, George VI and Cosgrove shelves in west Antarctica will be saturated with meltwater by the end of the century--a finding which echoes that of a study led by Jan van Angelen, also of Utrecht University, that was published last year in Geophysical Research Letters. [P67, The Economist (Feb 07, 2014)]

This, as they reported in December’s Nature Geoscience, contains some 140 bil- lion tonnes of liquid water. [P67, The Economist (Feb 07, 2014)]

Further explanation or description

Parenthesis

There is, for example, little Neanderthal DNA on the X chromosome (which, along with the Y chromosome, determines an individual’s sex). [P66, The Economist (Feb 07, 2014)]

Dr Forster and his colleagues think the aquifer they have found covers an area of 70,000 square kilometres (about the size of Ireland). [P67, The Economist (Feb 07, 2014)]

em dash (--)

For instance, genes affecting the production of keratin--an important component of hair and skin--showed more Neanderthal influence than most. [P66, The Economist (Feb 07, 2014)]

This would not matter as a one-off, but if it happened repeatedly as new firn formed the consequences could be serious--particularly if, in escaping, it caused more hydrofracturing or acted as a lubricant that encouraged previously stable ice to slip from its bed- rock into the sea. [P67, The Economist (Feb 07, 2014)]

How likely that sort of thing is to happen--and thus how much of a threat firn really is--has yet to be determined. [P67, The Economist (Feb 07, 2014)]

Enumerate

And two studies, one just published in Nature, and one in Science, have now looked in detail at this miscegenation, and tried to understand its consequences. [P66, The Economist (Feb 07, 2014)]

Emphasise

But the fact that so little is known about it emphasises a wider point. [P67, The Economist (Feb 07, 2014)]

Misc

Crucially, though the amount of Neanderthal DNA in any individual is small, the exact bits vary a lot from person to person. [P67, The Economist (Feb 07, 2014)]

Technically, Neanderthals may be gone. But their DNA ghosts linger on. [P67, The Economist (Feb 07, 2014)]