Synthetic trees are way more efficient in mitigating warming.

In the fight against climate change, trees are an ally. They suck in carbon dioxide, reducing the harmful greenhouse gases. But there’s a problem: we’re asking them to work overtime.

Trees can’t absorb enough of the carbon dioxide humanity is throwing at them unless we turn every inch of available land into a dense forest, according to Christophe Jospe, chief strategist at Arizona State’s Center for Negative Carbon Emissions.

But what if trees – or machines modelled after them – had superpowers? Artificial trees with otherworldly abilities are a great hope against climate change, since environmental experts say it’s not realistic to expect humanity to release significantly less carbon into the atmosphere. Our best bet might be to capture the excess carbon and store it or convert it into something useful, such as fuel.

Five years ago, a Boston group recruited two designers to develop artificial city trees. The trees they envisioned offered shade and would absorb carbon dioxide. The thinking was to place the trees where soil was too shallow to host traditional trees.

The group delivered great mock-ups, but little else has come from it so far. Finding funding is a challenge.

“You don’t want to be the first person to pay,” said Kimberly Poliquin, the director of ShiftBoston. “Scientists have figures, but you don’t know if that’s going to be the reality.”

Capturing and storing carbon isn’t yet the type of expense local governments and organisations can slide into their budgets. The cost of the technology is dropping, but not to a point where it’s affordable to install “forests” of these systems. Poliquin estimates an upfront cost of $350,000 for an artificial tree, but she expects prices to come down considerably. She hopes to develop a prototype of such a tree in one or two years.

There’s plenty of interest in removing carbon from the air. One method is to capture carbon directly from the smokestacks of power plants. Another method – which the Boston project targeted – is pulling carbon out of the open air, where it isn’t present in as much density. In theory, one square kilometre of artificial trees could remove 4m tons of carbon a year, according to the Center for Negative Carbon Emissions, which is developing a technology to work in open spaces.

Seven large-scale projects to capture and store carbon at power plants will arrive in 2016 and 20-17. Most are in the US and Canada. But more growth is needed before carbon capture and storage makes an impact on climate change. According to the Global Carbon Capture and Storage Institute, the 15 large-scale projects operating around the world can capture 28m tonnes of carbon dioxide per year. To keep climate change in check, we’ll need to process 4bn tonnes in 2040 and 6bn in 2050.

The Center for Negative Carbon Emissions is developing technology that it says is 1,000 times as effective as trees, per unit of biomass. The group is located in the desert because its technology responds well to warm, dry air and requires less energy in that environment.