Think Differently. Solve the Impossible.

Assume climate change is true. What could we do to solve it, other than reducing CO2 emissions?

Climate change conversations tend to converge on the same set of solutions: Reduce carbon dioxide emissions. Replace fossil fuels with renewable energy. Electrify transportation and buildings. Capture carbon. Buy carbon credits. Improve efficiency.

Those have a role. I want to ask a different question: What else could we do about its consequences besides reducing greenhouse-gas emissions?

I'm not asking whether CO₂ contributes to climate change. For this discussion, we can accept that premise and move on. I'm asking whether we've narrowed the solution space by concentrating heavily on one part of the system.

If the problems we experience include drought, flooding, extreme heat, changing precipitation, stronger storms, water shortages, crop losses and rising temperatures - there may be more than one place in the system where we can intervene.

Instead of beginning with a preferred solution, let's start with the problem and ask:
What are we trying to change?
 

1. Change the Amount of Energy

One approach is to change Earth's energy balance, without changing atmospheric CO₂. It's an active area of scientific research, described as solar radiation modification or climate intervention.

The National Academies has examined three approaches in particular: stratospheric aerosol injection, marine cloud brightening and cirrus cloud thinning. These don't all work the same way, and the terminology can be misleading. Cirrus cloud thinning, for example, is intended to allow more outgoing thermal radiation to escape, rather than reflect more incoming sunlight.

Stratospheric Aerosol Injection

The basic idea is to introduce small reflective particles, or precursors that form them,high in the atmosphere. More sunlight is reflected away from Earth. Less solar energy is absorbed. Temperature decreases.

We have some evidence that this physical mechanism works, as nature has performed versions of the experiment. Large volcanic eruptions can put aerosols into the stratosphere and produce measurable cooling.

That doesn't establish that deliberately doing it would be wise. Questions remain about atmospheric chemistry, ozone, precipitation, regional effects, how much material would be required, how long deployment would need to continue, and what happens if a large intervention is suddenly stopped.

The important point is, the intervention isn't with CO₂ - it's the incoming energy.
 

Marine Cloud Brightening

Instead of changing the entire atmosphere, this attempts to make certain low marine clouds more reflective. Particles, commonly proposed to be sea salt, would be introduced into the lower atmosphere. Under the right conditions, they could change cloud droplets and increase cloud reflectivity.

Brighter clouds reflect more sunlight.

The mechanism isn't hypothetical. Changes in cloud brightness associated with particles from ships have been observed. What remains uncertain is how reliably, where, and at what scale the effect could be  produced, along with the resulting regional climate effects.
 

Cirrus Cloud Thinning

High cirrus clouds present the opposite problem. Rather than trying to reflect incoming sunlight, the idea is to alter cirrus clouds so more outgoing heat escapes to space. The National Academies describes this as the most uncertain of these three approaches, with model results varying substantially.

I can't conclude that it doesn't work. The evidence determines the confidence we should have in each idea. The unfamiliarity of the idea shouldn't. That's a principle we should apply to every solution proposed.
 

2. Don't Change Temperature. Change Rainfall.

Now let's move downstream. Suppose the immediate problem isn't average global temperature - It's drought.  A farmer doesn't experience "global mean surface temperature." The farmer experiences: It didn't rain. Can we intervene? We've been trying to do that for decades.

Cloud Seeding

Cloud seeding may be the best-known example of weather modification.

Materials such as silver iodide are introduced into suitable clouds with the goal of encouraging the formation of ice crystals and increasing precipitation.

In the 1940s and 1950s, General Electric researchers working with the U.S. government conducted weather-modification research under Project Cirrus, including experiments involving precipitation and storms. My original podcast sent me down this historical rabbit hole, as I had thought of cloud seeding as a narrower technology. 

Once I started looking, the potential solution space became larger.Cloud seeding illustrates an important problem with environmental intervention.

Where does the intervention end?

If we increase precipitation in one place, what happens downwind? Did we create rain that otherwise wouldn't have occurred? Did we just change where existing moisture is precipitated? How far away can an intervention influence atmospheric conditions? How confidently can we distinguish the intervention from weather that would have occurred anyway?

That's doesn't mean cloud seeding doesn't work. We need to understand more before deciding where and how it should be used.
 

3. Could We Make Rain Without Adding Seeding Material?

This was one of the questions that interested me most. If we're going to intentionally modify weather, my preference would be to investigate methods that minimize introducing new and persistent substances into the environment. That lead to less familiar ideas.
 

Lasers

This is where skepticism needs to work in both directions. "Using lasers to influence rain" sounds futuristic enough that it's easy to dismiss. Don't. It sounds futuristic enough that it's easy to become excited and assume we've found a solution. Don't do that either. Ask what has been demonstrated.

Researchers have demonstrated laser-induced water condensation experimentally.

A 2011 Nature Communications paper reported field experiments in which femtosecond laser filaments induced water condensation and droplet growth under atmospheric conditions. Other laboratory work has produced condensation and precipitation in cloud chambers and investigated the mechanisms involved.

That's interesting. It does not establish that we can point a laser at the sky and make it rain over Phoenix. The questions are the same ones we should ask about every technology in this article:

What has been demonstrated?
At what scale?
Under what atmospheric conditions?
How much energy is required?
Can the effect be scaled?
What else does the intervention produce?

Researchers have identified chemical products associated with laser-induced atmospheric processes. Calling a laser approach automatically "chemical-free" is an oversimplification. That's why I don't want to conclude that lasers will solve drought, and I don't want to conclude that they won't.

Lasers are a proposed intervention, with experimental evidence, at limited scale. That's how I would treat an unfamiliar cloud-seeding technology, a new desalination process, marine cloud brightening or any other proposed solution. Lasers don't deserve more skepticism because they sound unusual.
 

4. Don't Change the Climate - Change the Consequences

Suppose we can't prevent a hurricane. Why does that mean our only remaining solution is to reduce the emissions that may contribute to the conditions influencing hurricanes? There's another question: Why does the hurricane cause so much damage when it arrives?

Can we move the intervention point?

We can change where we build, construct flood-control systems, improve forecasting and evacuation, and design buildings for greater wind and flood resistance. The climate doesn't have to change for those interventions to reduce the consequence.

The same applies to extreme heat.

Instead of asking how to reduce global temperature, we could ask how to reduce temperatures where people actually live.

Shade. Reflective roofs. Urban vegetation. Building design. Different pavement and surface materials.

Consider drought. 

The solution space includes water recycling, desalination, aquifer recharge, storage, irrigation efficiency and changes in what and where we grow. None of these individually "solves climate change."

They solve problems caused or worsened by a changing climate.
 

5. Can We Weaken a Storm?

This gets harder. A hurricane contains an enormous amount of energy. People have proposed ways of interfering with storm formation or intensity. In my original investigation I found proposals involving cloud microphysics, moisture removal, changes to sea-surface conditions, electromagnetic systems and directed energy. The patent literature contains plenty of inventive approaches.

A patent doesn't prove that an invention works. It proves that someone proposed an invention and persuaded a patent examiner that it met the requirements for a patent. That's where the investigation should begin. 

Take each proposal and ask:

What physical process is it trying to change?
Has the process been demonstrated?
How much energy or material would be required?
Can it operate over the necessary area?
Would changing one part of a storm weaken the larger system?
What happens somewhere else if it succeeds?

Maybe an idea survives those questions. Maybe a ten-minute calculation shows that scaling it would be absurd. Either result advances the investigation. The correct standard isn't, "That sounds crazy." Nor is it, "There's a patent, therefore it must work."

Show me how it works.
 

What Problem Does Each Solution Solve?

This is where climate discussions become clearer. Consider what each intervention is trying to change:

Notice what's missing. CO₂. Climate is a system. Systems have more than one intervention point.
 

Who Gets to Change the Weather?

This may be harder than the engineering. Imagine we develop a reliable method for increasing rainfall.

Who decides where it rains?

Suppose one state increases precipitation, and another claims that intervention reduced rainfall downwind. Who owns atmospheric moisture? Who is liable?

Imagine we can weaken a hurricane. What if weakening it also changes its path? A city that would have been hit is spared. Another is hit instead. Who authorized the intervention? Who bears responsibility?

Take the same technology internationally. If one country can intentionally alter precipitation, temperature or storms, neighboring countries have an obvious interest in what it does. This isn't hypothetical as a governance issue.

The United States has had federal weather-modification reporting requirements for decades. The relevant law doesn't make weather modification illegal, as I said in my original podcast. It requires people engaging or attempting to engage in weather modification activities to submit prescribed reports.

There's an international treaty with an ominous-sounding name: The Convention on the Prohibition of Military or Any Other Hostile Use of Environmental Modification Techniques—ENMOD. It's easy to shorten that into, "the UN banned weather modification." That's not what it says. The treaty prohibits specified military or hostile uses of environmental modification. It explicitly says its provisions shall not hinder environmental modification for peaceful purposes.

The existence of the treaty tells us something interesting. Governments were thinking enough about environmental modification in the 1970s to negotiate rules governing its hostile use. Today, as climate-intervention technologies are investigated, the governance question becomes even more important.

Being able to change something doesn't tell us who should be allowed to change it.
 

Cause, Process or Consequence?

There are three broad places we can intervene.

Change the cause.

Reduce greenhouse-gas emissions. Remove greenhouse gases already in the atmosphere. This is where most climate policy discussion occurs.

Change the process.

Alter incoming solar radiation. Change cloud properties. Influence precipitation. Investigate whether storms can be weakened. This is climate and weather intervention.

Change the consequence.

Make cities cooler. Make buildings more resilient. Store more water. Protect against floods. Adapt agriculture. Redesign infrastructure. All are attempts to solve problems at different points in the same system. That leads back to the question that started this investigation.
 

What If We Solved Climate Change Without Reducing CO₂?

I don't mean we should stop trying to reduce emissions. I'm asking what happens when we stop requiring every climate solution to begin there. Assume climate change is occurring and greenhouse gases contribute to it. Put those questions aside for a moment.

A community doesn't experience a global CO₂ concentration. It experiences heat, drought, fire, flooding, storms, water shortages and changing growing conditions. What if we start with each of those problems and work backward?

What variables can we change?
What technologies already exist, and what technologies have been proposed?
Which ones survive scrutiny? Which ones fail when we calculate the scale?
Which create a worse problem somewhere else?
Which deserve more research?

The National Academies itself describes climate intervention approaches as possible complements to mitigation and adaptation, while emphasizing their substantial uncertainties and risks. That's a useful way to think about the larger problem. We don't have to choose between reducing CO₂ or investigating everything else. We can expand the solution space.

Some ideas will fail. Some may create unacceptable trade-offs or only work locally. Some ideas we haven't seriously considered may turn out to solve a specific problem extraordinarily well.

Start with the problem.

Then ask where in the system we can change it.

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About the Author

Daniel Stih (danielstih.com) is an aerospace engineer, software engineer, indoor environmental consultant, and author of 12 books. For more than 30 years, he has investigated complex problems spanning engineering, technology, the built environment, and human decision-making. His work explores how evidence, assumptions, and systems shape the conclusions we draw—and whether we're solving the right problem. Learn more about his approach in Why I Think This Way.