During a recent Facebook Live Q &A session, Representative Alexandria Ocasio-Cortez (D-NY)  told viewers that she so feared a future of climate change that she woke up at “like 3:30am” worrying about the fate of the planet. A few days later she shared a video of the damage inflicted on the Bahamas by Hurricane Dorian and the message:

“This is what climate change looks like: it hits vulnerable communities first. I can already hear climate deniers screeching: ‘It’s always been like this! You’re dim,’ etc. No. This is about science & leadership. We either decarbonize&cut emissions, or we don’t & let people die.”

The New York congresswoman’s position, like that of many of the Democrats currently running for president, is that widespread death and destruction will ensue if people aren’t willing to pay the price of her Green New Deal. This view was reiterated repeatedly during CNN’s seven-hour climate-change town hall where even purported moderate Joe Biden defended the Green New Deal. When moderator Anderson Cooper asked him if “it goes too far, is it unrealistic?” Biden retorted “No, it’s not.”

The plan, embraced by Sen. Bernie Sanders, Sen. Elizabeth Warren and others, would cost tens of trillions of dollars, with some estimates as high as $94 trillion in the first 10 years.

Some of AOC’s critics dismiss her claims as mere fearmongering. “Climate change is always an extinction-level event,” notes David Harsanyi in The Federalist, who highlights decades of doom-and-gloom climate predictions that didn’t pan out.

Meanwhile, the debate over what role humans play in the planet’s warming, and whether the current warming trend is outside historical norms, continues to rage.  Critics of the Green New Deal note that achieving all of the carbon reductions proposed in the Paris climate accord would only reduce global temperatures 0.05 degrees by the year 2100.  “The Paris agreement on climate change is already an incredibly expensive way of helping very little,” says Professor Bjorn Lomborg of the Copenhagen Consensus Center.

But let’s assume for a moment that, as Ocasio-Cortez argues, we must “do something” drastic like the total decarbonization of our society in the face of warming temperatures and rising tides. How much would it cost to mitigate the consequences of climate change rather than attempt a complete overhaul of the US economy, the lifestyles of 330 million people, and western society in general?

For years, universities, state environmental agencies and think-tanks have been modeling sea level rise and coastal flooding, and the cost of solutions to offset the effects and prevent damage.  A study in New Jersey following Hurricane Sandy estimated that an 8.2-mile seawall in an area of Bergen County would cost less than $400 million to engineer, build, and maintain, and would cut losses from weather-related events by $1 billion or more.

Researchers at the University of Florida have been creating economic models for cost/benefit analysis of flood mitigation efforts in Miami-Dade County, which could be adapted to other regions. The City of Miami Beach “plans to invest $500 million for SLR adaptation. The city has already undertaken several adaptation measures such as improvements of sewer systems to prevent saltwater backflow and construction of pump stations to assist in keeping the streets dry,” the researchers note. They argue that mitigation would provide savings at a 38:1 ratio.  That is, for every dollar spent on improved sewer systems, flood abatement, etc., residents would prevent $38 in damages.

The Yale School of Forestry and Environmental Studies explores several such studies, and extrapolates that, conservatively, the nationwide cost of projects to prevent coastal damage due to sea-level rise  “could run well into the hundreds of billions of dollars.”

Let’s say the cost of protecting our entire U.S. coastline would be $500 billion — or round it up to an even $1 trillion. That’s a lot of money–about 25 percent of the most recent federal budget, in fact. But it’s a drop in the bucket compared to the  $30 trillion, $50 trillion or $94 trillion estimates for the Green New Deal.

In addition, the savings achieved by these projects are likely to be far more immediate, since the solutions—walls, pump systems, changes in construction, etc. provide immediate relief, as opposed to promising a gradual change in the atmosphere that would then theoretically change the earth’s climate.  And flood prevention plans would be implemented at the state and local level, where the stakeholders understand the impacts of changing climate better than Washington DC.

Rising sea levels are just one part of the projected climate change. Warmer weather also means longer growing seasons, more agriculturally viable land and a host of other benefits.  Nobody is arguing that the benefits outweigh the potential costs, but rather that the net costs of attempting to prevent climate change vs. mitigating its effects should be considered.

In 2009, University of Sussex environmental economist Richard S.J. Tol issued a paper that estimated that climate change would actually increase global economic output for the next few decades, before turning into a net negative around 2075. Other academics disagree, insisting that acting now will save even more money later.

But with outspoken activists like AOC demanding a total re-tooling of western economies and tens of trillions of dollars in spending, it’s hard to make the case that the Green New Deal approach is a money-saver.  Instead, more people are beginning to ask whether paying the costs to solve climate-related problems might be smarter than pursuing a hypothetical utopia with zero guarantees.