European Athletics wants historic records rewritten because of a lack of credibility following a doping scandal.
"If that's what it took for the good of the sport then that's the way I would have to go," said Warner.
GB's Paula Radcliffe, who would lose her 2003 marathon world record, previously dubbed the idea "cowardly".
Britain's Colin Jackson would also lose his 1994 indoor 60m hurdles world record of 7.30 seconds.
Radcliffe said European Athletics' idea was "heavy handed", while Jackson said clean athletes "should not get caught up in this".
"They [Radcliffe and Jackson] love athletics and understand the greater good is what matters, but we've got to get to a better defined set of proposals, and we're not there yet," Warner told BBC Radio 4's Today programme.
Athletic's world governing body - the International Association of Athletics Federations (IAAF) - will discuss the proposals at a meeting in August.
The proposals are a response to last year's McLaren report, which uncovered widespread doping in sport - and athletics in particular. Russian athletes are banned from international competition unless they can satisfy strict criteria to show they are clean.
Warner believes some of the records set prior to 2005 were "iniquitous", adding: "Today's athletes can't get close to them because they were drug-fuelled."
One key proposal from European Athletics is that blood samples must be stored for 10 years after a record is set.
The IAAF has stored blood and urine samples only since 2005 and current records that do not meet the new criteria would remain on an "all-time list", but not be officially recognised as records.
Warner, who took charge of UKA in 2007, also warned this summer's World Championships in London would not be "100% clean", stating the battle against doping was "an arms race".
He will leave UKA after 11 years immediately after the World Championships and has already handed over chairman duties to Richard Bowker.

The unnamed 29-year old suffered multiple, severe stab wounds to her head and body in what police described as an "extremely brutal" attack.
She was attacked yards from her home after getting off a bus in Krithia Road, Dagenham, at 21:40 GMT on Monday.
Police say they believe the attack was carried out by a stranger but are "keeping an open mind".
Passers-by attempted to help the woman, who remains in a critical condition in a hospital in east London.
Due to the nature of the attack investigators do not have a description of a suspect at this point and there have been no arrests.
Police appealed for two women who stopped to help the victim, or anyone else with information, to contact them.
DCI Gary Holmes, of Homicide and Major Crime Command, told BBC London: "This is a really brutal and horrific stabbing of a young lady coming home from work.
"That attack has left her in a terribly critical condition, currently in hospital in a life threatening condition and we are desperate to locate the person who committed... that attack."
Outgoing UK Athletics chief Ed Warner has backed plans to erase world records set before 2005, adding that athletes affected understand "the greater good".
[NEXT_CONCEPT]
A woman in east London has been left fighting for her life after an apparently random knife attack.