Beyond the Data Update — Climate Change and Health – From Science to Practice


Iskander: Hello I'm Dr. John Iskandar and welcome to CDCs, Beyond the Data. I'm here again today with Dr. George Luber, chief of CDC's Climate and Health program. Dr. Luber, since we did our Grand Rounds on climate change in health in December 2014, there are some new scientific findings that are important to this field. Can you bring us up to speed on some of those? Luber: Sure, absolutely. It's nice to see you again John. At the end of 2014 we had some evidence that 2014 was gonna' turn out to be a warm year and in January of this year our National Oceanic Atmospheric Administration which collects this temperature data globally, reported that indeed 2014 was the hottest year on record. This represents the global averaged land surface temperature and it's consistent with the trend that we've seen since the 1980s of subsequent years being hotter than the rest.

Iskander: Another issue that we talked about during the session was extremes of climate events and their impact on human health. Do we have some new information about that as well? Luber: Absolutely, so, as we discussed the hallmark of climate change is that the average temperature for an area increases over time. Well we're also seeing changes in the variance, which is the frequency of events, of weather events, that are anomalous, that are on the outside the normal range of events, and these are called extreme events. Recent analyses published in nature climate change have showed that indeed with regards to temperature extremes and precipitation extremes, or heavy rainfall events, that we are observing an increase in these events, have observed and will continue to see an increase in them over time.

Iskander: So, I think people in our audience may be aware of some of these events, but can we, even if we can't relate it directly to a single event, thinking about for example, the issue of drought. What do we know about the relationship between extremes of heat and drought and ultimately impacts on health? Luber: Well there's a number of dimensions to drought that are important that are linked to climate changes. Certainly the cause of drought has to do with a number of factors, some of which are not climate related. It could be a human made in that we take too much water out of the system or managing improperly. The climate change has been predicted to increase the frequency, intensity, and magnitude of droughts through a number of mechanisms. First the increase in temperatures, increase the rate of evaporation, drying out soils faster.

But we're also seeing subtle changes in rainfall that also affect the drought situation and area. So take a look at California for example, we are just entering into the spring and summer season and during this time of year most of the water in California comes from melting of the snowpack, which is a critical storage mechanism for much of the areas that are currently affected by the drought. As we enter the spring season, California has 6% of its normal snowpack. This is actually a record of low snowpack in the Sierra Nevada, which portends very serious consequences for the summertime. And the reason were having a decreased snowpack is that rainfall precipitation is more frequently coming down in the form of rain in the wintertime than snow as we would typically expect, and this because most of the warming that we're seeing across the globe is occurring in the winter months.

So we're getting elevated winter temperatures that are changing snow precipitation from snow to rain and that rain runs off the surface, it doesn't get stored in the system like snow or ice would, that would be available for use later in the year. So there's a number of dimensions to that. Add to that the increase summertime temperatures which will certainly increase the rates of evaporation, drying out soils and further exacerbating the drought. Iskander: So clearly as we move, as we move into the summer months there's going to be obviously concern about not only drought, but also extremes of heat really throughout the country. What is CDC and what are its partners doing to help respond to some of the potential public health effects of these extremes of heat? Luber: So the CDC in the climate health program has an initiative called "the climate ready states and cities initiative", and through this initiative we work with partners at the state and local level to do a number of activities that help them prepare and build resilience against the types of events like drought that they will experience in their jurisdiction. Now, granted California will be dealing with a distinctly different set of issues than our grantees in Maine.

But they all use the same basic framework, we call it the brace framework, to assess the climate impacts in their region, identify those individuals and locations that are most vulnerable to those impacts. Estimate the magnitude of burden of disease, either morbidity or mortality that will be the result of these changes and then put in measures to adapt or prepare, prevent those health effects from happening. And our colleagues in California are doing a number of activities relevant to the drought, including assessing vulnerability to the wide range of exposures that the drought will bring. It will certainly degrade air quality, drier soil leads to more airborne dust. We have the increased frequency of wildfires that is a result of a drying climate that also degrade air quality as well.

And, match that with higher summertime temperatures and exposure to extreme heat and you have a number of intersecting exposures that will certainly fall on those most vulnerable, the children, the elderly, those with respiratory conditions, etc… And California is determining the location of these multiple populations in order to get the message out, to monitor and prevent health effects from occurring. Iskander: That's a very good example of what, what's being done in one state. For people in our audience who want to know what their state or their city is doing, are there some new resources since we first did this session that they might want to consult? Luber: Certainly, we've been working with American Public Health Association to describe the range of activities that our grantees, 18 states and cities, are conducting to prepare for the health effects of climate changes, serve as role models for other health departments that might want to engage in this topic. We produce a report called, "Adaptation in Action", it's posted on our website as well as APHA's website and it describes in detail what particular activities the states are doing, from focusing on harmful algae blooms in the Northeast states, Lyme disease in certain communities, waterborne disease and others, and certainly extreme heat exposure and others.

All of these are relevant or related to the health impacts of climate change, but the framework in which they're addressing these is consistent throughout, but it's just that the subject matter is different. Iskander: Thank you very much for joining us again Dr. Luber. Luber: Thanks, it's been a pleasure. Iskander: Please join us next time for Beyond the Data..