Cryptic Crossword clue help?

In a higher position among hundreds to win trophies (4) CUPS

("up" in Cs and of course C = 100 in Roman numerals)

Jeers when militay quarters seen (8) - BARRACKS

(means jeers + military quarters)

Paper about in the morning (4) REAM

(ream of paper, re = about + A.M. morning)

Crossroads at which to bury part? (12) INTERSECTION

(bury = inter, part = section , crossroads = intersection)

100 short, act on list of bequests as one wishes (4,2) AT WILL

(2,4 - not 4,2)

(100 short act = take C out of act leaving "AT", list of bequests = "will", as one wishes = "At will")

Study not lasting in our era? (12) CONTEMPORARY

(Con = study, temporary = not lasting, contemporary = in our era)

It is a disadvantage to lure defender out (8) DRAWBACK

(disadvantage = drawback, to lure = draw, defender = "back")

Twice act for extinct animal (4) DODO

(twice "do")

Singer is bighead and idiot (4) BASS

(head letter of big = "B" + as.s)

Concerning plea for the same again (10) REPETITION

(concerning = Re , plea = petition, same again = repetition)

Mongrel has one ring that is a valuable object (5) CURIO

(mongrel = cur + 1 + O = ring)

This team has a pretentious air (4) SIDE

(side = team + it sounds like "sighed")

There is nothing in crazy maniac becoming unconcious (2,1,4) IN A COMA

(anagram "O" for nothing and "maniac")

Hits fishing vessels (6) = SMACKS

(means both hits and fishing vessels)

Puts extra 500 among advertisements (4) ADDS

(ads with "D" ie 500 in Roman numerals)

Examinations in which results are poor also (5) ORALS

(anagram of "R" for "results" + "also" and means examinations)

Concerning Crossword Clue

Global warming?