As early as the 19th century, when large-scale industrialization was still getting underway, scientists were already theorizing a “greenhouse effect” where increased levels of carbon dioxide (CO2) in Earth’s atmosphere could cause global warming.

In the 20th century, CO2 levels rose higher than anything in the geological record. By the late 1970s, scientists had begun warning about the potential consequences of global warming—but calls to slow or stop this trend by decreasing carbon emissions were ignored.

Here in the 21st century, climate change has become a reality. Average surface temperatures have risen, and so have ocean temperatures. The oceans are also becoming more acidic. Sea levels are rising. Ice sheets and glaciers are shrinking. Extreme weather events are becoming more frequent. Scientists now project that severe droughts, intense heat waves, violent hurricanes, wildfires, flooding, erosion, diseases, and disruptions in food and fresh water supplies will impact health, property, agriculture, and the world economy. Worst-case scenarios include forests dying, cities drowning, populated areas turning to desert, deadly crop failures, desperate refugees, and mass extinctions.

Since prevention didn’t work, some scientists now hope that new technologies can help control global warming and dangerous changes in the Earth’s climate, before these nightmare scenarios come to pass.

The good news is: there are many such technologies and projects being explored and developed. For instance, “carbon capture” technologies aim to remove excess CO2 from the atmosphere through various methods. Some are aimed at major sources of emissions, like power plants. Others simply filter the air around us. Futuristic artificial materials are being developed and improved, taking the form of membranes and crystals that are able to absorb large amounts of CO2. Researchers have even created “artificial leaves” that imitate real plants in the way they process atmospheric CO2. Other initiatives include “mineralizing” CO2, which means turning it into rock, or even turning into fuel like methanol, or carbon fibers used for industry.

In addition to carbon capture, there are ambitious “geoengineering” measures being considered. One is stratospheric aerosol injection, which involves adding sulfur compounds to the atmosphere in order to reflect solar heat and reduce warming effects. Another is spraying water into the air over the ocean to “brighten” clouds that reflect solar heat, while thinning out other clouds around the planet that trap heat. Other strategies include artificially making land surfaces more reflective, and cultivating ocean growth of phytoplankton that absorb CO2.

The bad news is: these technologies have never been tried on the kind of scale necessary to help reduce the effects of climate change. We don’t know what unplanned side effects could result from tampering with the atmosphere. Some geoengineering tactics could change weather patterns in unpredictable ways, or increase humans’ exposure to hazardous ultraviolet rays.

We also don’t know how well these methods will work, or how much they will cost. Even getting rich nations to invest in more traditional methods of reducing emissions, such as reforestation, wind and solar power, and electric transportation, has been difficult and slow. Convincing world leaders to devote the necessary money and effort to things like carbon capture is not likely to be any easier. There is also evidence that reducing emissions significantly enough to make an impact will be much more expensive than previously estimated, with many poorer countries simply unable to afford necessary changes.

In addition, even highly effective carbon capture or geoengineering still won’t solve the problem of climate change. Because the world waited too long before addressing this problem, even optimistic future scenarios assuming worldwide cooperation can only aim for keeping climate change somewhat in check, rather than stopping it. At this point, “saving the day” means things like preserving a small percentage of coral reefs from destruction, or preventing famine from devastating some poor countries, or limiting rises in sea level so that we do not have to abandon all coastal cities.

Achieving even that much will require combining these new scientific and technological approaches with the same drastic reductions in greenhouse gas emissions that scientists have been recommending for decades. In other words, this new solution won’t help unless we also finally adopt the old solution. However, the old solution requires more radical change and sacrifice than leaders have been ready to accept. This is what people are referring to when they complain about a “lack of political will.”

Individual people are making changes in their lifestyles to reduce their “carbon footprint,” but this mainly just helps us feel better about our personal choices. To make the kind of difference needed to roll back climate change, the whole world will have to change the way we grow food, travel, and manufacture goods. Naturally this will create massive and unpredictable economic changes, a nightmare for politicians who get elected by promising prosperity and growth. There is also a common belief that protecting the environment means hurting the economy. Of course, if nothing is done, climate change is expected to wreak havoc on world economies. Plus, economic growth is not much use if the world is falling apart.

Both the public and politicians tend to think short-term, but climate change is a long-term problem that requires facing a scary future that is rapidly becoming the present. Unfortunately, the combination of short-term thinking and denial (many people still refuse to acknowledge that climate change is real, despite the findings of the vast majority of scientists) results in nothing getting done. In addition, divisive politics leads people to adopt positions on issues like climate change based on identifying with a political party or cultural group, rather than based on science.

The bottom line is: science may be able to help, but it can’t “save the day.” There is even the danger that promoting miraculous-sounding scientific “fixes” will allow leaders to continue putting off the hard choices needed to cut emissions. Instead, we must think differently, act differently, and demand that our leaders do the same.