Climate change involves and impacts every system within the planet, from ecosystems to fresh water distribution. It’s infinitely complex. But while many causes are still unknown, we do know that the earth’s temperature is rising and that human activity is contributing to the temperature spike noted since with the Industrial Revolution.

While common climate change culprits include increased use of fossil fuels and rising levels of CO2, other causes are lesser known. For example, methane gas from biodegradable waste is a major greenhouse gas. Scientists now say biodegradable waste in dumpsites is contributing more methane to the atmosphere than they thought. Identifying contributors like this helps us make smart choices when it comes to things like waste management.

With that in mind, here are some other causes and implications of climate change that make it something we should take seriously.

Overpopulation is a Bigger Cause Than You Think

It’s been found that human overpopulation and climate change are scientifically linked. As the influential political economist Robert Malthus noted, “The power of population is indefinitely greater than the power in the earth to produce subsistence for man.” In other words, it’s much easier to make new humans than it is to support them. The increase in population brings more demand for natural resources, more land dedicated to farming, more deforestation, and elevated carbon emissions. Population growth and climate change are a perfect feedback loop.

But the implications of maintaining this system are disastrous for the planet and human civilizations. The demand for natural resources to support 7.5 billion people already exceeds what the planet can provide. Experts estimate that humans currently use the equivalent of 1.7 earths worth of resources. That means it takes 18 months for the planet to regenerate 12 months worth of resources. This situation is untenable.

And the challenges to population control are staggering. Most industrialized nations like the U.S. balk at the idea of implementing population controls. But allowing numbers to grow will only meet an inevitable confrontation with fewer resources. Without addressing overpopulation, climate change will continue. And with it, we will see an increase in migration, war, displacement, crime, poverty, disease, and shorter life expectancy.

Climate Warming is Changing Our Oceans

Oceans are big regulators of the planet’s temperature. They absorb and trap heat from the atmosphere — acting like a giant sponge that protects the planet from overheating. The oceans’ layers heat at different rates, with the top layer being the warmest. But over the last 50 years, climate change has increased the temperature of our oceans by 0.3°F. And the ocean’s top layer is now warming at a rate of .2°F per decade.

But what happens when our oceans get too warm? Well, quite a bit. For one, warming oceans increase the rate of melting glaciers and ice sheets. The runoff contributes to rising sea levels, which is already making the consistent flooding of coastal cities and towns a new normal for residents. Less habitable coastal land will bring massive property losses and increased migration by displaced people.

Warming oceans also threaten critical ecosystems like coral reefs, which provide habitats for millions of the world’s aquatic life. The Great Barrier Reef of Australia is already seeing massive “bleaching” effects from warming oceans. And experts predict coral reefs may become all but extinct by 2050 if current trends continue.

Another climate change threat to our planet’s oceans is from increased “acidification” — the rise in acidity from dissolved carbon dioxide. Like heat, oceans also absorb CO2 from our atmosphere and produce half of the oxygen we breathe. Since the Industrial Revolution, increased CO2 emissions have raised the levels of ocean acidification by 30%. Higher acid levels affect calcified shellfish like clams, oysters, and corals by eating away at their protective layers. Any threat to these aquatic species could destroy the entire ecosystem — a system that supplies 15% of the protein intake for 4.3 billion people.

Climate Change is Affecting Your Health

Climate change brings an increase in the severity and frequency of climate events. More flooding, stronger hurricanes, longer heat waves, and rising pollution are a few consequences of a warming planet. These heightened weather phenomena also raise the risks to public health in the following ways:

Less freshwater supplies

A warmer climate means melting glaciers. The roughly 150,000 glaciers around the world store about three-quarters of our freshwater supply. As more glaciers near the earth’s poles retreat, their abundance of fresh water runs into the oceans, becoming undrinkable salt water.

Less freshwater will lead to contaminated water supplies and waterborne diseases like cholera and dysentery (already responsible for 3.4 million deaths each year). Rising sea levels will cause sewage backups and water contamination for coastal cities, exacerbating the situation.

A rise in disease-carrying insects

While warming climates will devastate some species like polar bears, it will be a boon for others like mosquitoes, ticks, and crop pests. Stagnant water and growing populations of insects will spread more mosquito-borne illnesses like malaria and the Zika virus. And more insects means hardier diseases that mutate to become resistant to treatment.

More drowning deaths

Larger and more frequent flooding events will lead to higher losses of life via drowning. Floods are the leading cause of death among all weather-related disasters that happen in the U.S. Drowning while driving is a big problem, specifically for flash floods. People desperate to make it home or to safety too often take the chance to cross flooded areas in their cars. But it only takes 18 inches of water to lift a vehicle, roll it over, and trap the victims inside. Flash floods will be a hallmark of climate change, as sudden and violent downpours will inundate populated areas near river valleys and coastlines.

There are many things you can do to help combat and adapt to climate change. Take part in recycling campaigns, use public transportation, turn off your electronics when you’re not using them, and eat less meat. But one of the most effective things you can do is share what you know. Find reputable information and spread the word to your family, friends, and anyone who will listen.