Some impacts of climate change are direct. Others are indirect. It is important to understand the difference between the two. This will help us understand how climate change works and what can be done to reduce its impacts.

Defining Direct Impacts

Let’s start with direct impacts. Direct impacts are measurable changes in Earth’s natural systems. They are directly caused by warming temperatures. These are likely the impacts you think of first. They include rising sea levels, melting ice caps, and shifting rain patterns.

Another direct impact is the increased likelihood of floods, storms, and wildfires. Not every natural disaster can be clearly linked to climate change. A single wildfire might have happened whether the world was heating up or not. However, climate change makes the chance of that wildfire happening much greater. It also makes it more likely that the wildfire will be severe. This increased likelihood and severity of natural disasters is an important kind of direct impact. It means disasters impact more people. It also means that more of our money and energy is spent on recovery.

Some important direct impacts of climate change are harder to detect. Global warming is altering many natural systems. It causes changes in plant life cycles and increases ocean acidification.

Ocean acidification is a change in the chemical composition of our oceans. It happens when chemicals in the water react with carbon dioxide in the air. Because of human- caused air pollution, the amount of carbon dioxide in the air is quickly increasing. Ocean acidification is causing the disappearance of coral reefs, which are all-important for ocean life.

Defining Indirect Impacts

Climate change will alter many of Earth’s natural systems. Yet these are not the effects you are most likely to feel. The everyday systems we rely upon for our food, housing, and security are also affected by climate change. We call these changes “indirect impacts.” They result from climate change interacting with human systems.

Picture this: Climate change increases the frequency and length of droughts in a region, a direct impact. The droughts cause widespread crop failures and reduce freshwater availability — indirect impacts. Because food and water are harder to find, many people in the region, especially kids, don’t get enough to eat and drink, another indirect impact. This makes them weak. As a result, they are much more likely to get sick, yet another indirect impact.

A single direct impact of climate change can easily result in many indirect impacts. Other types of indirect impacts include increased heat- and cold-related illnesses, breathing problems, damage to housing, and disruption to supply chains. All of these things can lead to increased costs, forced migration, unrest and war.

But Why Differentiate?

All of the impacts mentioned above are the result of climate change. So why do we need to make a distinction between indirect and direct impacts? The categories help us understand problems and identify solutions.

Direct impacts can easily be understood, tracked, and even predicted by climate scientists. The way to prevent them is quite clear. To reduce their chance of happening, we must lower our greenhouse gas emissions. Greenhouse gases trap heat high up in the atmosphere. Over time, this causes average global temperatures to rise. The buildup of greenhouse gases is mostly caused by burning fossil fuels like oil, coal, and natural gas, which are used for things like electricity, heat, and transportation. Reducing the use of fossil fuels is the major way to prevent continuing climate change.

Dealing with indirect impacts is more complicated. There are two main types of solutions. First, we can reduce indirect impacts by reducing direct impacts. Second, we can adapt to climate change, meaning we can change our behavior and the way we design things. For example, we can design housing to be naturally cooler in the summer. As communities around the world face the impacts of climate change, adaptation solutions will become increasingly important. They will help us maintain our way of life while protecting human health and well-being.