* It's when all greenhouse gas emissions are balanced out through methods to remove them from the atmosphere

* This includes carbon storage through forests, farms and underground

* The Paris Agreement - a pact to limit global warming to "well below" 2C above pre-industrial levels - calls on nations to achieve net zero emissions in the second half of the century

WHO'S ON BOARD?

* More than 70 countries including the UK and Canada have committed to producing net zero emissions by 2050

* China aims to reach net zero by 2060

* Every Australian state and territory has also committed to the long-term target

WHAT ARE AUSTRALIA'S LEADERS SAYING?

* The Morrison government is committed to the Paris target and keeps its language firmly on net zero in the "second half of the century". It wants to focus on technology in order to do this

* Federal Labor's target is for net zero by 2050, but the opposition - which could only put the goal in place by winning government at the next election - hasn't explained how it would happen

WHAT IS INDUSTRY DOING?

AGRICULTURE

* National Farmers Federation - supports a 2050 net zero target, seeing climate change as an opportunity for farmers to find new ways of making money, and a challenge in terms of a drier climate and worsening natural disasters

* Meat and Livestock Australia - explicit target to achieve carbon neutrality by 2030. Currently working on a 2025 strategic plan

BUSINESS

* Business Council of Australia - supports a transition to net-zero emissions by 2050 and says if Australia can meet its emissions reduction targets without carryover credits, it should

* Ai Group - supports a move to net zero by 2050

RESOURCES

* BHP - aiming for net zero by 2050, linking management pay to these targets from 2021, developing a medium-term target this year

OTHER SECTORS

* ANU - aiming to be below net-zero emissions well before 2050

* BANKING - two-thirds have a net zero by 2050 target or are on a pathway to it for internal operations; only a quarter have net-zero target for investment and lending portfolios

* PROPERTY - almost half listed property companies have commitments to reduce emissions in line with Paris, three in 10 have pledged for net zero by 2050 and another 14 per cent don't have an explicit goal but are on the pathway

* LOCAL GOVERNMENT - of the nation's 57 largest councils (covering more than half the population), nearly three in five have net zero by 2050 target for operational emissions and almost two in five have net-zero target or aspiration for community emissions.

* DOCTORS. The Australian Medical Association backs the net zero by 2050 target as a health response to climate change, as do a number of other groups such as Climate and Health Alliance and Doctors for the Environment.

Australian Associated Press