There is consensus among experts that climate change is happening – and that it is playing a role in multiplying negative health impacts across the globe. These could exponentially increase as we approach the environmental tipping point scientists have warned us about.

However, a recent survey revealed that while the majority of Americans believe that climate change is causing harm, most do not believe that it is affecting them personally. They're wrong: climate change is already affecting all of us through negative impacts on our health independent of age, health status, socioeconomic class, or geographic location. Our personal health is intrinsically tied to the health of this planet, and the planet has a breathing problem.

For humans, breathing is the act of taking in oxygen and exhaling carbon dioxide. Adults do it an average of about 16 times a minute. In complementary symmetry, our planet has a "breathing" cycle that works in the exact opposite way: plants on land and plankton in water take in carbon dioxide and release our life-sustaining oxygen.

The harmony has been broken

But there's a growing amount of carbon dioxide with a decreasing amount of oxygen. This has been termed climate change because of the downstream effects this imbalance creates. Simply put, humans have produced more carbon dioxide through the burning of fossil fuels than the shrinking population of plants and plankton can compensate for. The harmony has been broken.

In a human, this sort of breathing distress would lead to death without medical intervention. As an emergency medicine physician, I encounter people when their health is threatened in this way. This can involve problems with not getting enough oxygen into the body, trouble getting the carbon dioxide out, or both. We must keep those levels in perfect harmony to survive, and the two are deeply interconnected.

The parts of the planet's breathing cycle, like our human one, are intertwined. Water cycles and weather patterns don't respect the man-made barriers that we call states or countries. Thus, carbon dioxide produced in one location has an effect on the opposite side of the globe. Oxygen on one side of the world will make it to the other side in a little over a year.

This interconnection results in a true moral and ethical dilemma because the regions of the world that have produced the most carbon dioxide, and thus contributed the most to climate change, often have the fewest health impacts. Many people living in developed countries have food sources, houses, jobs, and city infrastructure that are not directly tied to the health of the land around them. The resources they are fortunate enough to benefit from creates a buffer.

Meanwhile in developing countries, livelihood is often directly intertwined with the land. People depend on their own crops for survival, live in fragile structures that cannot sustain extreme weather, and have jobs easily influenced by the natural world. This lack of resources creates an enormously small margin for adaptation in a world with climate change.

No exceptions

However, no one's health is entirely spared. The negative health impacts are numerous, complex, and arise in a variety of ways. On the most fundamental level, as carbon dioxide levels increase, there is a subsequent increase in global temperatures, sea level, and extreme weather.

This leads to such phenomena as extreme heat waves, environmental degradation, changes in where disease-carrying insects live, worsening air pollution, increased allergen production, decreased water quality, and decreased nutrition in crops. Sample impacts on health can be more heat-related illnesses, increased lyme and dengue infections, more asthma exacerbations, increased waterborne diseases, malnutrition, and mental health impacts. In its most severe form, people are forced from their homes; a displaced population faces more health challenges than perhaps any other. Extreme weather forced more than a million people from their homes in the United States in 2017 alone.

One of the easiest changes to recognize is increased heat, to which the kidneys and heart can be especially vulnerable. My patient Levi* was a 30-year-old Boston construction worker who was struggling to make ends meet as he cared for his family. Working overtime, he developed kidney failure after laboring intensely in the scorching summer heat. Though humans are inevitably adapting through an increasing resilience to heat, worsening extreme heat from climate change will likely result in more deaths in the future.

For many infectious diseases, factors that contribute to its spread - such as the geographic distribution of insects and their breeding seasons - are changing with climate change. In the US, lyme cases have more than doubled since 1990. My patient Jerod presented to the emergency department after having dismissed an earlier rash. However, after developing a severe headache and neck stiffness, he was diagnosed with lyme disease that had invaded his brain. We believe he contracted it from a region that didn't have lyme previously. Meanwhile, worldwide there are other infectious diseases that are increasing in incidence, such as dengue.

Breathing and injuries

Air pollution is also worsened by climate change, with urban centers being especially affected. Combine this with other factors like increased smoke from wildfires and increased allergen production, and those with underlying lung diseases experience more issues. One example is the meek four-year-old girl named Fang who was admitted to the hospital four times last spring for problems with her asthma. Or another patient I cared for some years ago in Haiti. Six-year-old Ricardo suffered many exacerbations of his asthma, likely from the perfect storm of severe air pollution in the city of Port-au-Prince coupled with rising temperatures. While living an ocean apart, their asthma responded to the same triggers.

The other impact of climate change that is most easily identified is injuries during or after increasingly extreme weather events, especially given the record-setting year of 2017. These events not only cause devastation locally; they can also have unexpected effects on health in far-off places. For example, there is now a shortage of IV fluids in the US. If you walk into an emergency department in Boston, you will likely not receive IV fluids unless you are significantly ill. The reason for this shortage is that Hurricane Maria devastated the production plants in Puerto Rico, yet another example of the true interconnectedness we have in this globalized world.

Just like air, climate change is ubiquitous. Thus, it affects every human on this planet. And as our planet struggles to "breathe" and maintain its health, our interconnectedness mandates that our health is equally in dire jeopardy. There are things that can be done today to help, but we must act before it is too late.

*Names were changed to protect patient identities.