Global emission reduction needs to be seven times higher: expert report

So says the head of the world's peak atmospheric science agency following the release of a new report compiling the latest scientific research from seven major authorities.

In a stark warning to policy makers, industry and the public, the report warns of "devastating" problems caused by climate change has blasted lack of urgent action.

You might also like:

"Without ambitious action, the physical and socioeconomic impacts of climate change will be devastating. Irreversible physical changes in the climate system, known as tipping points, cannot be ruled out and could have significant global and regional consequences," it says.

The World Meteorological Organization's (WMO) United in Science report includes assessments from the Intergovernmental Panel on Climate Change, UN-supported and independent carbon monitoring agencies, and the British Met Office. It found there is a near 50/50 chance the world's annual mean temperature will temporarily exceed 1.5°C above pre-industrial levels in the next five years.

1.5°C is the "preferable" limit to global warming set out in the Paris Agreement signed by 196 countries in 2015, backing the stated ambition to keep warming to "well below" two degrees.

Last year nations adopted the Glasgow Climate Pact which includes commitments to mitigate climate change, lower emissions and support vulnerable developing countries.

"Greenhouse gas concentrations are continuing to rise, reaching new record highs," says WMO secretary-general Professor Petteri Taalas.

"Fossil fuel emission rates are now above pre-pandemic levels, the past seven years were the warmest on record, cities - which contribute 70 per cent of global emissions - are highly vulnerable to climate impacts."

The United in Science assessment of global carbon emissions reduction targets says national goals need to be at least seven times more ambitious, otherwise "irreversible physical changes" in the global climate system could not be ruled out.

Among its findings, the report found:

Lockdowns were found to have little impact on curbing the level of atmospheric greenhouse gases. Originally, a 5.4 per cent dip in these gases was attributed to lockdowns in 2020. Initial data analysed by the Global Carbon Project indicates carbon dioxide has increased a minimum of one percent above the same period in 2019.

This increase has been largely driven by the United States, India and most of Europe. It comes despite 23 nations - including the US, European countries, Mexico and Japan - reducing carbon dioxide emissions in the decade prior to the pandemic.

The WMO also found oceans are warming at their strongest rate for two decades. Around 90 per cent of the Earth's accumulated heat is stored in oceans and the five years from 2018 to 2022 had the highest rate of heat capture than any other half-decade on record.

Meanwhile the UK's Met Office predicts a 1.1-1.7-degree higher mean global near-surface temperature in each of the next five years. Although there is a small probability that the average temperature during this time will exceed 1.5 degrees, there is a strong chance that this milestone will be reached in at least one of these years.

There is a risk of ''baking in'' change to the global climate if atmospheric tipping points are exceeded. The United in Science report emphasises this will take place in the absence of "ambitious action".

Australia recently legislated a target of 43 per cent emissions decrease on 2005 levels by 2030. Critics say this is insufficient for Australia to play its part in global carbon reduction efforts, given it is one of the largest pollution emitters on a per capita basis.

The Climate Council, for example, wants to see a 75 per cent reduction by the end of the decade.

Among the frequent projections for nations like Australia, are exacerbated temperature extremes and increased hazardous events, some of which are beginning to emerge. Tuesday's declaration of a third consecutive La Nina event, for instance, has only happened three times in the past century.

Although La Nina is a natural climactic event, increasing frequency and severity may be indicative of the changing climate from human-generated carbon emissions. The last two years have seen unprecedented flood damage occur along Australia's east coast in connection with the cooler, wetter conditions La Nina typically brings.

"The projections are that these things continue," says Professor Lisa Alexander, a climatologist from the University of New South Wales.

"And that's not surprising, given what we know about how humans interact with the climate system, and what they can potentially do. Extremes of temperature, extremes of rainfall, these are definitely things not only that we've seen, but we will continue to see at an accelerated rate in the future."

Amid record-breaking heat in the UK, European droughts and record flooding in Pakistan, early warning systems are becoming increasingly important for nations seeking to reduce the impacts of more extreme climate events on human lives.

Emeritus Professor Neville Nicholls from Monash University's school of earth, atmosphere and environment has worked as a lead author for several IPCC reports since 1990. He said the latest assessment from the WMO was a sobering report showing the world would not be able to avoid some of the detrimental effects of global warming.

"Although efforts to slow emissions must continue and accelerate, we are left with the uncomfortable fact that we will have to adapt to the changing climate," Nicholls said.

The report comes after recent data showed that some parts of the world may experience over 200 days of dangerous heat index temperatures, and up to 90 days of extremely dangerous days a year by 2100.