Exxon Mobile CEO and Chairman Rex Tiller

ExxonMobil Chief Executive Rex Tillerson acknowledged the risks posed by climate change at the company’s annual meeting on May 29, but he stressed that the real-world consequences of rising atmospheric carbon dioxide levels remain unknown.

“We view climate change as a serious issue, it does present serious risk,” Tillerson told shareholders.

But he cast doubt on the certainty with which forecasts can be made about what climate change may mean in practical terms. “Notwithstanding all the advancements that have been made in gathering more data, instrumenting the planet so that we understand who climate conditions are changing…our ability to project the future with any degree of certainty continues to be very limited,” he said.

“Our ability to understand all the relationships between emissions, the environment and the feedback loops continues to be one of the scientific community’s grand challenges,” said Tillerson.

Tillerson said that while 350 parts per million is a frequently-cited safe upper limit for atmospheric CO2 concentration, the number does not represent a specific set of implications. “I cannot conclude that there’s something magical about 350,” he said.

He added that the Intergovernmental Panel on Climate Change (IPCC) acknowledges limits to the accuracy of its models’ climate change forecasts. “They publish a very broad range of possible outcomes because they acknowledge the model’s competencies are questionable,” Tillerson said. “To suggest that 350 versus 450 somehow is a known outcome is just not respecting the competency of the models.”

And a lack of good information about the consequences of moving past specific atmospheric CO2 levels complicates preparation. “Our ability to predict the consequences is just not that good.”

Weighing climate risk against economic risk

Tillerson stressed that alternatives to fossil fuels do not yet exist at a cost and scale that could supplant fossil fuels without severe negative economic and social consequences.

“We do not have a readily available replacement for the energy that provides the means of living that the world has today – our standard of living, but equally and perhaps more importantly, the 2 billion people on the planet that live below anything that we find acceptable,” he said. “Windmills won’t do it, solar panels won’t do it, biofuels won’t do it.”

“We do not see a viable pathway, any known technology today, to achieve the 350 [ppm] outcome that is not devastating to economies, societies, and people’s health and welfare around the world,” Tillerson said. “What good is it to save the planet if humanity suffers in the process of those efforts, if you don’t know what the outcome is going to be?”

He called for focusing on progress in technologies that can reduce emissions without adverse economic repercussions. “We’re only going to find that way forward if we can put all of our energies into that, and less into the most extreme viewpoints at either end of this debate, which is we’re all doomed or we’re all crazy. Because neither of those is right.”

Pending the discovery or advancement of such technologies, ExxonMobil continues to tout the potential of efficiency as a means of managing climate change risk – a sentiment recently echoed by prominent public figures, such as US Energy Secretary Ernest Moniz and International Energy Agency Executive Director Maria van der Hoeven.

What do shareholders say?

A group of ExxonMobil shareholders has proposed that the company’s board set quantitative greenhouse gas emissions reductions targets for the last several years.  Shareholder support for the proposal, according to preliminary voting results, slipped to 26.8% this year from 27.1% last year.