Just 100 companies have been identified as accountable for more than 70 percent of the world’s greenhouse gas emissions, according to a report published Monday.

The Carbon Majors Report, published in collaboration with the Climate Accountability Institute, found that more than half of industrial emissions worldwide could be sourced to only 25 corporate or state-owned businesses.

The report said the scale of historical emissions is large enough to have contributed significantly to climate change since 1988. The same year the Intergovernmental Panel on Climate Change was established.

Typically, large-scale greenhouse gas emissions data has been collected by country level. However, the Carbon Majors Report focused on fossil fuel producers in order to emphasize the role firms and their investors could play when attempting to tackle climate change in the future.

The highest emitting companies over the last three decades included companies such as ExxonMobil, Shell, and BP.

All three major oil and gas companies have faced heavy criticism for their respective environmental records in the past and have since embarked upon green investments. ExxonMobil announced in May last year it would start exploring carbon capture and storage, while BP and Shell have increased investment in renewables in recent years.

“If the trend in fossil fuel extraction continues over the next 28 years as it has over the previous 28, then global average temperatures would be on course to rise around 4 degrees Celsius above preindustrial levels by the end of the century,” the report said.

Global average temperatures reaching such a level are likely to have potentially disastrous and irreversible effects on the planet’s environment. In 2015’s landmark Paris accord, almost all world leaders agreed to make sure global warming would stay “well below” 2 degrees Celsius and “pursue efforts” to limit a rise in temperature to 1.5 degrees Celsius.

On June 1, President Donald Trump announced the U.S. would withdraw from the agreement and start talks to re-enter or renegotiate a new accord.

The report also found that around a fifth of global industrial greenhouse gas emissions were supported by public investors. Therefore, it follows investors could have a significant impact in influencing the actions of board-level decision-making moving forwards, the report added.

Meantime, almost 100 companies including Apple, Google and beer giant Anheuser-Busch InBev have committed to 100 percent renewable power under the RE100 initiative.

The initiative is made up of some of the world’s biggest businesses, all of which are committed to renewable energy.