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AHEARN: It’s The Researcher’s Perspective. I’m Ashley Ahearn.

Climate change is not just a problem for rivers and reservoirs that are running dry or forests that are seeing more wildfires, or polar bears who are running out of frozen habitat.

It’s a problem for people, and the National Institute of Environmental Health Sciences is tackling that problem. Joining me to talk about it is Dr. John Balbus. He’s a senior adviser for public health at the NIEHS.

Dr. Balbus, thanks for joining me.

BALBUS: Thanks for having me.

AHEARN: Let’s start with the current state of affairs. What sorts of human health impacts are we seeing now in the population that could be attributed to climate change?

BALBUS: Well, that’s a good question, and it’s not as easy a question to answer as you might think, and part of it has to do with this difference between climate and climate change and weather. Remember, climate is the 30-year running average of the weather, and so to attribute actual events and human health impacts to that is a little tricky. Humans are really affected mostly by weather, so to the extent that we can attribute changes in weather to climate change, that’s one way that we do it.

So if we think about climate change itself, there are some things that are going on that we’re witnessing that do have human health impacts, and one of the easiest to understand is what’s going on with pollen. Because of the changes in climate, the pollen season for people suffering from allergies is getting longer. There was just a study that came out in the last year that shows that the pollen season is 13 to 27 days longer,1 and people with allergy know that the longer they’re exposed to pollen, the more severe their allergies can be. People with asthma may have a higher risk of having asthma exacerbations and those kinds of things.

The World Health Organization also does an extensive and comprehensive look at causes of death around the world, and they’ve looked at the increase in deaths from five specific causes related to climate change, and they’re looking at things like malnutrition and diarrhea, malaria, flooding, and heat stress-so not all the different things that climate change is related to, but some of the more prominent climate change related health impacts. And they’ve gone and, using the epidemiology studies that we have so far that try to give this idea of how much does climate change increase the risk of these conditions, they’ve estimated the number of people who died way back in 2000, 11 years ago, as a result of climate change, and estimated about 150,000 people died around the world because of that.2

AHEARN: What do you see as the most important or threatening human health issues associated with climate change, Dr. Balbus?

BALBUS: In the near term we’re seeing a lot of problems from more extreme heat and heat stress. We know that people who have underlying lung disease have more problems when it gets very hot out, especially if that heat goes along with higher levels of ozone and other kinds of air pollution, and that can put people in the hospital because they have trouble breathing, and their medication isn’t working. We also know that people that have underlying cardiovascular disease and diabetes have problems with heat stress-both putting stress on the heart but also putting stress on the kidneys-and that when we have these bad heat waves there are a lot more people showing up with acute kidney failure because of the dehydration and the stress on the kidneys that goes with that heat. So it’s going to be things like that. It’s climate change as an additional stressor on top of problems that people already have with their health and the kind of problems that we already see.