Considering Ice Melting.
A participle phrase where melting( a present participle) acts as an adjective to the noun ice.
its easily discernible as you can use an adjective clause,or relative clause, and get the exact same meaning.
As in ->
Arctic animals are now in danger because of the ice which/that is melting.
Considering because of ice melting due to global warming
A non-finite subordinating conjunction clause of the conjunction duo because-of which relies on the tense of the main clause - Arctic animals are now in danger.
Global Warming is a different matter, although similar.
Global warming is a a common phrase,a gerund phrase, where the present participle warming, this time around, acts as a noun which is modified by the adjective global.