Pipeline companies are bracing for an ongoing battle with environmental activists who are targeting the nation's infrastructure in their bid to stop a surge in North America's oil and natural gas production.

Executives from some of the biggest energy infrastructure companies in Canada and the United States say their industry had been surprised by the escalation and sophistication of the so-called "keep it in the ground" activists. They said they need to fire back on multiple fronts, including the courts, the halls of regulatory agencies and social media.

The battle over pipelines reached a fever pitch in 2016 and 2017 during tense standoffs between law enforcement and activists who camped out for months in solidarity with the Standing Rock Sioux Tribe to prevent the completion of the Dakota Access pipeline in North Dakota.

That tipping point, along with a series of acts of pipeline sabotage, illustrates how climate-change activism is now focused on infrastructure, the executives said during a panel on Wednesday at the CERAWeek by IHS Markit conference in Houston.

"The effort is much more intense. There's more opposition. It's more organized and ... the tactics have evolved," said Steven Kean, president and CEO of Kinder Morgan, whose $7.4 billion Trans Mountain pipeline expansion project faces threats of Standing Rock-style protests.

Kean said the new tactics include the October 2016 incident in which activists in several states disrupted crude flows from cross-border pipelines by shutting emergency valves. The potentially dangerous action could have caused the lines to rupture under pressure, he said.

Pipeline opponents have also grown more sophisticated in the courts, hiring experienced counsel to deploy novel legal defenses, said Russell Girling, president and CEO of TransCanada, the company behind the Keystone XL pipeline, which was blocked by the Obama administration over climate concerns but later approved by President Donald Trump.

While some of the so-called pipe turners in the coordinated attacks were convicted of felonies and sent to prison, Girling noted, others were allowed to argue that they broke the law to protect fellow citizens from the impacts of climate change.

"They have become extraordinarily adept at finding those places both in courts and the regulatory process to stop this up," he said.

Pipeline makers need to anticipate challenges from activists and make sure their applications to regulators are airtight, leaving no room for appeals that can delay multibillion-dollar projects, Girling said.

Kelcy Warren, president and CEO at Energy Transfer Partners, said an environmental disaster could have occurred when someone burned a hole in the company's Dakota Access pipeline infrastructure last year, though no oil was flowing through the line at that point.

"I think you're talking about somebody who needs to be removed from the gene pool," said Warren.

The executive said the industry was too slow to respond to social media campaigns that he said perpetuated lies about pipeline companies and their projects. In the future, the companies need to be proactive and devote resources to counteracting those campaigns.

Sharon Wilson, senior organizer for Earthworks, said grassroots groups are seeking to protect their homes from pipeline leaks and explosions and prevent entrenching dirty fossil fuels for decades to come.

"I don't know what 'lies' Kelcy Warren is attributing to opponents of Energy Transfer Pipelines, but I surely hope he isn't referencing the Dakota Access Pipeline's multiple leaks, the state of Ohio's lawsuits over Rover Pipeline's spills, or the state of Pennsylvania's halting the Mariner Pipeline for 'egregious' violations," she said in a statement to CNBC.

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