The aspirational Paris target of 1.5C maximum warming will be beyond our reach if the economy returns to pre-Covid normal. Technological solutions, although necessary, are not sufficient.

This is crunch time. We cannot burn all of Earths fossil fuel resources without causing a large increase in global average temperatures with disastrous impacts. If we want to limit global average temperature to 2C above the pre-industrial level with high probability, we must stay within a certain budget of remaining emissions. This dwindling amount is the called the global carbon budget for 2C.

However, the 2C target is not safe, as demonstrated by the increased frequency and severity of droughts, heatwaves, floods and terrible bushfires around the world with just one degree of global heating. If we want to have a high probability of limiting global average temperature to 1.5C above the pre-industrial level (the aspirational Paris target), then the carbon budget becomes about one-third the amount of the 2C target.

For those who like arithmetic, the two global budgets are given here. The estimated corresponding crunch times are as follows:

• 2C target with 66% probability: about 29 years from 1/1/2020 at current level of emissions;
• 1.5C target with 66% probability: about nine years from 1/1/2020 at current level of emissions.

Global emissions have been increasing up to and including 2019.

Different calculations based on different methods give somewhat different carbon budgets and crunch times, some smaller and some larger, but they dont change the conclusion that the 1.5C target will be beyond our reach if the economy returns to pre-Covid normal.

Its true that the majority of emissions comes from energy production by fossil fuels, that 100% renewable energy is now technically feasible and affordable, and that renewable energy production has been growing steadily. But, apart from the Covid pause, so has the global economy and, as a result, energy demand. Renewable energy has been chasing a retreating goal and time is of the essence in stopping runaway global heating.

The technological key to transforming the energy sector to renewables is electrification. On the positive side, renewable electricity generation has been gradually overtaking growth in electricity demandits now about 27% of global electricity consumption. But so far renewable electricity has made little impact on the growth of fossil-fuelled transportthis is likely to change rapidly from the mid-2020s when electric vehicles are expected to become generally competitive. Renewable electricity has had negligible impact to date in replacing fossil-fuelled heating in the residential and industrial sectors.

The bottom line is that transitioning the whole global energy sector is occurring too slowly to avoid climate catastrophe and therefore that non-technical measures, outlined below, are needed.

As a rich country that has one of the highest per capita greenhouse gas emissions in the world, Australia is even behind the global average in doing its fair share of responding to climate crisis. I suggest that a fair distribution of the remaining global carbon budget among countries would apply the Universal Declaration of Human Rights that Australia voted for in 1948 in the United Nations General Assembly. In this case each person in the world would be entitled to an equal fraction of the remaining emissions budget.

On the basis of equal per capita emissions, Australia would receive only one third of one percent of global CO2 emissions. This would give Australia the equivalent of nine years of current emissions for our fair share of the 2C target and just three years for the 1.5C target counting from 1 January 2020. Assuming a linear reduction (i.e. equal steps down to zero in megatonnes of emissions) would give Australians 18 years for the 2C transition and six years for the 1.5C transition.

But Australias total GHG emissions in 2019 were essentially the same as in 2013. Electricity emissions have declined, thanks mainly to the growth of renewable energy, Most progress in transitioning electricity has been achieved in South Australia and the A.C.T., while Victoria is implementing some effective policies. Despite the progress in electricity, emissions from transport and non-energy industrial processes, including non-electrical heating, have increased. As a result, we are not making any progress in reducing our total emissions.

One of the few benefits of the disastrous Covid-19 pandemic has been the temporary reduction in GHG emissions. However, in addition to deaths and disease, the price has been a big increase in unemployment and under-employment. This raises the question: how can we develop policies for returning people to work without returning to the old high-emissions economy?

Clearly our governments must stimulate and support employment in low-emission economic activities such as renewable energy, energy efficiency, childcare, nursing, community health, education, public transport, electric vehicle infrastructure, cycleways, pedestrian areas, biodiversity conservation, land management (including managing national parks), green hydrogen and the ABC. Some of the above activities of strategic importance to the economy will need government assistance in setting up manufacturing industries.

A future, socially responsible government could fund the above activities by:

• ensuring that multinational corporations selling goods and services in Australia are taxed;
• cancelling proposed tax cuts;
• reforming negative gearing and the capital gains tax discount in the residential property market;
• reforming superannuation tax concessions;
• imposing super profit taxes; and
• introducing a financial transactions tax.

Environmental taxes, such a carbon tax, would also be of great value and these could be made acceptable to the voting public by returning the money raised to every citizen in equal amounts. Surely thats a more constructive policy than current proposals to simply increase the rate of GST and to extend its scope to foods?

To conclude, solutions to the climate crisis are available, but its doubtful whether the governments of Australia, the USA and the rest of the world (with the possible exception of some European Union countries) will rise to the challenge in time.