The 20 companies responsible for a third of all carbon emissions

Half of all global fossil fuel emissions since 1751 have been emitted since 1990.
Half of all global fossil fuel emissions since 1751 have been emitted since 1990. Photo credit: File

More than a third of all greenhouse gas emissions over the last 50 years have been caused by just 20 fossil fuel companies.

New data from the Climate Accountability Institute shows these top 20 companies have collectively contributed 480 billion tonnes of carbon dioxide and methane since 1965.

This is the equivalent of 35 percent of all fossil fuel and cement emissions.

The organisation says it chose 1965 as a starting point as "recent research has revealed that by mid-1960s the climate impact of fossil fuels was known by industry leaders and politicians".

"We focus on the fossil fuel companies that, in our view, have produced and marketed the carbon fuels to billions of consumers with the knowledge that their use as intended will worsen the climate crisis."

According to the report, half of all the global fossil fuel and cement CO2 emissions since 1751 have been emitted since 1990. 

The companies listed had "significant moral, financial and legal responsibility" for the current climate crisis, the report concluded. It called on the responsible companies to commit to reducing future production of carbon fuels and emissions.

"Companies leading this transition will prosper, and laggards will perish."

The Climate Accountability Institute is a US-based independent research institute focusing on human-influenced climate change.

Pressure has mounted in recent years for more to be done to combat climate change. 

Last month, tens of thousands took to the streets all across New Zealand calling for the Government and businesses to take action.

They were inspired by Swedish teenager Greta Thunberg, who has become the public face of climate-change activism.

In 2015, New Zealand signed on to the Paris Agreement, and in May the Government announced its Zero Carbon Bill, which laid out a 30-year plan aiming to limit global warming to no more than 1.5degC.

An independent Climate Change Commission would also be established, Climate Change Minister James Shaw announced at the time, to "support our emissions reduction targets through advice, guidance, and regular five-yearly 'emissions budgets'".

A full list of the top 20 carbon-emitting companies:

1.       Saudi Aramco, Saudi Arabia

2.       Chevron, USA

3.       Gazprom, Russia

4.       ExxonMobil, USA

5.       National Iranian Oil Co.

6.       BP, UK

7.       Royal Dutch Shell, The Netherlands

8.       Coal India, India

9.       Pemex, Mexico

10.   Petroleos de Venezuela

11.   PetroChina

12.   Peabody Energy, USA

13.   ConocoPhillips, USA

14.   Abu Dhabi, United Arab Emirates

15.   Kuwait Petroleum Corp. Kuwait

16.   Iraq National Oil Co, Iraq

17.   Total SA, France

18.   Sonatrach, Algeria

19.   BHP Billiton, Australia

20.   Petrobras, Brazil