If our planet reaches its tipping point, and that is a real possibility, our environment, economy and standard of living will be irreversibly damaged and the Opposition's harping on the impact of a carbon trading scheme and other carbon reduction measures on Australian jobs, fuel prices and the cost of living will be academic.

On a per capita basis, Australians are the world's largest emitters of carbon and we need to be a world leader in carbon reduction.

Rather than seeking to wrong-foot Kevin Rudd by engaging in petty political points-scoring and alarmist rhetoric, the Opposition needs to act responsibly and in partnership with the Government on this most pressing and critical issue.

The Opposition also needs to acknowledge that efforts to curb climate change create great economic opportunities, particularly for Australia, if our efforts are not stymied by cheap political points-scoring.

Patricia Saunders, Chapman

Flying half-truth

The article ''Qantas landing gear 'not working''' (July 28, p1) reported that ''these returns [by aircraft] were purely precautionary and the aircraft could have proceeded ... in complete safety''.

A half-truth at best.

Aircraft such as the Dash 8 are certified to transport category standards.

These standards require that in an engine failure after take-off situation, climb performance is measured ''with the undercarriage retracted''.

With the undercarriage not being able to be retracted, under such circumstances, certified performance would not have been achievable, and with the huge drag of the Dash 8's undercarriage extended, the aircraft would have been anything but safe.

Climb performance (one engine) most probably would have been negative for all of the time the undercarriage was not up, and the aircraft most probably not able to maintain height (one engine).

Notwithstanding, the captain would have been too busy flying the aircraft accurately to have any time to work out how to get the undercarriage up by alternate methods.

I wonder if the baulked approach situation was considered? This is where the aircraft is required to go round from late final approach.

With the undercarriage down (and unable to be retracted) and full flap, initial performance would be marginal on two engines.

Perhaps the aircraft should have been grounded until the undercarriage had been fixed.

Ian Baldwin, Hughes

Tax check at home

I note a US Senate committee investigation of tax havens and revelations about the commercial affairs of Frank Lowy and his family (''Lowy refuses to answer tax haven questions'', July 27, p20).

I suggest the Australian Senate now sets up a standing committee with real powers to investigate the tax affairs of high-wealth individuals in Australia.

Certainly working families who can't avail themselves of complex avoidance schemes would be interested to know the level of commitment of our top earners to contributing a fair share of tax to the Australian community.

John Passant, Kambah