Climate change is making heat waves stronger and more frequent, air pollution worse, and allowing vector-borne diseases to expand their range. It's also compromising our drinking water, causing more extreme weather events, and impacting our mental health. And the costs will be great: just this June, the World Health Organization estimated that in the twenty years after 2030, climate change will cause "approximately 250,000 additional deaths per year, from malnutrition, malaria, diarrhoea and heat stress."
Thanks to climate change, we're already seeing stronger, longer, and more frequent heatwaves. People -- particularly the very young and very old -- don't cope well with in these conditions. In 2003, some 70,000 people died in the European heat wave, and last summer more than 2,000 perished in India and southwest Asia. But the problems from heat aren't just happening on the other side of the globe. Here in the U.S., people who spend a lot of time outdoors -- farm workers, construction crews, even athletes -- are feeling the effects of warmer days. The Texas Rangers want to build a new billion-dollar stadium with a retractable roof, an expensive feature that owner Ray Davis called "a must to counter the scorching heat in the summer." But most people don't have the resources to spend to adapt to new conditions like that, and so instead will just suffer in the heat.
2. Air Pollution
Air pollution, whether it's the heavy smog that shrouds Los Angeles or the fine dust that burns our lungs in China, isn't causing climate change. But climate change is making air pollution worse! And the stakes are high: air pollution already causes an estimated 7 million premature deaths across the globe each year. Air pollution is made up a variety of things, including ground-level ozone, particulate matter, nitrogen oxides, and carbon monoxide, and when we breathe those in, we get sick. As the planet grows warmer due to climate change, the reactions that form ground-level ozone -- one of the most dangerous things for us to inhale -- happen faster. And climate change also affects our weather patterns. As the earth grows warmer, we're seeing more high-pressure systems. And a high-pressure system stuck over an area can trap local pollution and particulate matter, preventing it from being blown away, and so the area's residents will keep breathing it in.
3. Vector-Borne Diseases
What do zika, chikungunya, dengue, and malaria have in common? They're all vector-borne diseases spread by mosquitos. And insect ranges are often determined by climate. So if climate is changing, that means the geographic extent of many of these diseases will, too. In some cases, a disease could move into a new region where it's never been seen before, like we're seeing in Canada with Lyme disease, a devastating condition that used to be so unusual north of the border, it wasn't even on Health Canada's list of treatable diseases. In other instances, as it gets warmer a disease could move out of its current region -- like our research has shown is likely to be the case for dengue in Texas in the summer. And in yet other cases, a disease could re-emerge in a place where it was eradicated a century ago -- like malaria in Chicago.
4. Water-Borne Diseases
Climate change is also leading to more deaths from diarrhea, which is already the second leading cause of death for kids under five around the world. How is that, you may wonder? Well, a warmer atmosphere speeds up the hydrological cycle, leading to more periods of extreme precipitation. Heavier rainfall often means higher risk of flooding. And flooding -- particularly in nations where drinking water is at risk of being contaminated with garbage, animal manure, and even human waste -- can be deadly. "Runoff from more frequent and intense extreme precipitation events will increasingly compromise sources of drinking water through increased introduction of pathogens and prevalence of toxic algal blooms. As a result, the risk of human exposure to agents of water-related illness will increase," says the 2016 Climate and Health Assessment.
5. Extreme Weather Hazards
Extreme weather events, such as hurricanes, heavy downpours, and flooding, all of which can affect our health and well-being, and we're seeing more of them as the climate changes. These events can harm or even kill us; they can prevent us from getting the medical care we need, turning a trivial concern into a life-threatening illness; and they can sweep away cars, homes, businesses, and harvests. "Earth has always experienced epic storms, debilitating drought, and biblical floods. But lately it seems the treadmill of disruptive weather has been set to fast-forward," writes Paul Douglas, a professional meteorologist and -- like me -- someone whose faith motivates his concern on this issue. Let's zero in one just one type of extreme event: a hurricane. There are all sorts of risks that crop up in the aftermath of a hurricane. If your power goes out and you have to run a generator in your house, you run the risk of carbon monoxide poisoning if you don't set the generator up correctly. Or let's say it's flooding and your car gets swept away and you run the risk of drowning. Thanks to climate change, we're seeing more hurricanes and so are more exposed to these risks.
6. Our Mental Health
Climate change, and the increasing risk of weather extremes that accompanies it, has a direct impact on our mental well-being. "Many people exposed to climate related or weather-related disasters experience stress and serious mental health consequences ... [including] post-traumatic stress disorder (PTSD), depression, and general anxiety," says the 2016 US Climate and Health Assessment. Last year, when I was working with the city of Boulder on climate preparedness, an emergency room doctor told me that extreme weather is one of the biggest challenges they face in counseling people with long-term mental health issues. If a patient misses one appointment due to snow, flooding, or other situations that prevent travel, there is a big chance they will fail to keep their next one, and the next, and their problems -- some of which may have been on the road to recovery -- will resurface in full force. That's not all, though. Sometimes just thinking about climate change can overload us. As the American Psychological Association says, "mental health impacts of actual and perceived climate change include stress, anxiety, apathy, and guilt." When we view climate change as a huge global issue and we are only one human, we can be overwhelmed by fear, anxiety, and despair. But acknowledging those feelings is the first step to dealing with them.
7. Political Instability And Conflict
The seventh and biggest way that climate change affects our health is something you might never have thought about before -- through its impact on the political stability of failing states and nations. These past five years have shown in brutal clarity how a nation like Syria already teetering on the brink -- due to decades of conflict, corruption, and mismanagement of its natural resources -- can be pushed over the edge into disaster. Did climate change cause the Syrian refugee crisis? No. There were many factors at play. Did climate change contribute to it? Yes, it did. As one scientific study concludes, "Human-induced forcing has increased the probability of severe and persistent droughts in this region, and made the occurrence of a 3-year drought as severe as that of 2007−2010 two to three times more likely than by natural variability alone." Climate change increases the risk of conflict in the poor, unstable, and desperate regions of the world. Public health systems collapse, families will be driven into refugee camps, and attempts to flee to safer countries often end in unmitigated disaster and tragedy, with permanent and all too often even fatal impacts on millions of peoples' lives.
So, given all this, why should we care about a changing climate? Because it affects us, our families, our communities, and people everywhere: real people, particularly the poor, the vulnerable, and those who already lack the resources to cope.