Research into ways to engineer the Earth’s climate as a last-ditch response to global warming will be rendered “unviable” if the associated ethical issues are not tackled first, a leading environmental philosopher has warned.

Prof Stephen Gardiner, of the University of Washington, Seattle, told the Guardian that so-called geoengineering risked making problems worse for future generations.

Gardiner was in Sydney for a two-day symposium that aimed to grapple with the moral and ethical consequences of geoengineering, also known as climate modification.

Later this year, the United States’ National Academy of Sciences is due to publish a key report into the “technical feasibility” of a number of proposed geoengineering methods, which fall into two categories.

Carbon dioxide removal (CDR) tries to cut the levels of the greenhouse gas in the atmosphere and store it, for example, in trees, algae or underground.

A second category, known as solar radiation management tries to lower the amount of energy entering the Earth’s atmosphere from the sun by, for example, spraying sulphate particles into the stratosphere or whitening clouds.

Gardiner said political inertia was one reason why the world had failed to respond meaningfully to climate change and rising greenhouse gases.

“There’s a temptation for the current generation particularly in the rich countries to take benefits now and pass the severe costs on to the future,” he said.

“Arguably that’s one of the big reasons we have failed so far on climate policy because we have succumbed to that temptation.

“But when it comes to geoengineering, one of my biggest worries is that we might pick geoengineering as an intervention that replicates that pattern.

“We might try and adopt a quick technological fix but one that holds the worst impacts for a few decades without much attention to what happens after that. What does happen after that could be even worse than what would unfold if we just allowed the negative climate impacts in the near term to materialise.”

He said that it was time to engage with the ethical and moral questions now that major scientific institutions and a growing group of researchers were starting to consider geoengineering.

“We are still in the early stages and very few people have written and talked about this. The good news is that the major scientific reports generally do signal that they think there are major ethical, political, legal and social issues that need investigating. The crucial thing is whether we get beyond saying that as a throwaway line to actually dealing with those implications.

“Unless you can deal with these social and political issues then any kind of geoengineering would be unviable anyway – or at least any remotely ethically defensible version would be unviable.”

In 2009, a Royal Society report called for more research into geoengineering and concluded that CDR techniques “should be regarded as preferable”.

A proposed experiment to test a way to deliver particles into the upper atmosphere using a balloon and a one kilometre-long pipe was cancelled in 2012 after it was reported that two of the scientists involved had submitted patent applications that were similar to the techniques being proposed.

A study earlier this year in the journal Nature Communications comparing five different proposed methods of climate engineering found all were “relatively ineffective” while carrying “potentially severe side effects” that would be difficult to stop.

Prof Jim Falk, of the Melbourne Sustainable Society Institute at the University of Melbourne, told the symposium there were more than 40 distinct methods that could be described as geoengineering, including planting large numbers of trees and painting roofs white.

He said: “There’s a huge array of ideas and they go from local scale to intermediate scale to a global scale. The scale, the impacts and the risks all go up together.”

• Graham Readfearn’s travel and accommodation was paid for by the symposium organisers.