The notion that climate could underlie health conditions and sometimes unleash epidemics is not new to human thinking. We have long regarded climate trends as responsible for some of our collective conditions. However, today with the population density of the planet, we don’t have to look into the future to know that climate change is conducive to negative health effects. Climate change is already driving unprecedented extreme events and extreme heat. Sustained periods of high temperature overwhelmingly increases the problems, and when paired with the aforementioned events, both become directly responsible for mounting deaths from heart and respiratory disease as well as higher levels of pollen and ozone triggering asthma—even causing changes in tick-borne disease patterns that increase public health risks. The World Health Organization (WHO) reports that, “The direct damage costs to health (i.e. excluding costs in health-determining sectors such as agriculture and water and sanitation), is estimated to be between US $2-4 billion/year by 2030.”
On June 18th in New York, I spoke about these issues with Dr. Carlos Pérez García-Pando, a climate scientist at the Department of Applied Physics and Applied Math, Columbia University, affiliated to the NASA Goddard Institute for Space Studies, New York. Dr. Pérez García-Pando, who also holds a PhD in environmental engineering, has worked at the International Research Institute for Climate and Society in New York, the National Centers for Environmental Prediction and the Earth Sciences Department of the Barcelona Supercomputing Center. His research is mainly related to the understanding of aerosol processes and interactions within the Earth system. He contributes to the development of climate and atmospheric aerosol models and is involved multidisciplinary research focused on climate and health.
His ongoing research creates new information that makes it easier for us to understand the dynamic nature of climate trends and how they impact our health. Improving these climate models could be a large lifesaver.
His core research interests are atmospheric particles in the atmosphere and how these particles affect climate, ocean biochemistry, air quality and health. To study these issues he develops and applies models ranging from descriptions of particles in atmospheric and Earth system models to climate-based statistical models of infectious disease transmission. His recent published research is on epidemics of meningococcal meningitis.
As we work to take care of ourselves through floods, storms, other extreme weather events, and as global warming progresses, this information will be required. It will shape governance and could make the difference of whether or not we fall ill.
GN Your recent research has focused on climate and health. In a study you co-authored this year you quantified the relationship between climate conditions of wind and dust and meningitis outbreaks in the Sub-Saharan, Africa. This climate statistical modeling can now be used as a forecasting tool to aid vaccination efforts. Has your scientific evidence helped determine a health-work plan for Africa’s entire meningitis belt?
CPGP Meningitis has been a big public health concern in Africa during the last century, affecting thousands of people every year and is one of the most feared diseases in Sub-Saharan Africa. So how does this work? WHO, the World Health Organization, has put in place a standard procedure to react to meningitis epidemics that occur every year in different parts of the region. During the dry season, as the Harmattan, a dry and dusty West African trade wind coming from the Sahara desert affects the region, the number of meningitis cases increases. Traditionally, the response has been reactive, which means that once an epidemic evolves in a specific district, WHO decides to vaccinate that district and vaccines are deployed. This was because available vaccines did not provide long-term immunity, and the idea of vaccinating a few hundred million people at risk every two years was unreasonable because of logistic and economic reasons. For this reason we tried to improve the reactive vaccination strategy. We know that there’s a relationship between the dry and dusty climate and meningitis in the region. We have been looking at this relationship in order to develop a prediction tool that could aid a timely vaccination of the belt’s population. Recently, the deployment of a conjugate vaccine that provides long-term immunity has superseded this strategy but only targets one serogroup, (a group of bacterial species that are antigenically closely related), and other serogroups may be problematic in the future. The type of prediction model we have developed at Columbia University and NASA could help improve the reactive strategy of WHO. Now, we test the validity of these prediction models in collaboration with decision makers.
GN It was long suspected that the weather and climate affected the occurrence of meningitis, and even other diseases like malaria. How does research data support this?
CPGP Malaria is a vector-borne disease. Vector-borne diseases rely upon organisms, named vectors, such as mosquitoes. For malaria, a lot of progress has been made in the understanding of the host-parasite-vector interactions and their biology, particularly through laboratories. For other diseases like meningitis, the mechanisms that explain the epidemics are more difficult to understand. Epidemics of meningitis are triggered by bacteria that are transmitted from person to person through respiratory droplets. Transmission and infection depend, among other issues, on social interaction, climate and the susceptibility of the population. However, some of these aspects are difficult to measure and there is a lack of laboratory studies that would allow understanding certain key interactions. Because of this lack of knowledge we quantify statistical associations between risk factors and the disease with the hope of using these associations for prediction.
GN How exactly does wind, sand, and dust relate to meningitis?
CPGP That’s a very good question. Basically, there are several factors we have identified as potential climate drivers for the disease. One is low humidity, and another, the dust level in the air. There are several hypotheses on the effects of dust upon meningitis. One posits that these particles irritate and damage the mucous, allowing the bacteria to penetrate into the blood stream and trigger the disease. Another hypothesis is that iron contained in the dust—a nutrient for bacteria—promotes colonization and proliferation of the bacteria in the respiratory system, increasing transmission and/or infection. Why we consider these as hypotheses? Because up until now we have had no direct evidence. I am involved in some initiatives to promote laboratory studies to look at mechanisms. Currently we have statistical associations and we need to look at the mechanisms in the lab.
GN There are studies out stating that El Niño events are strengthening because of global warming, and these extreme weather events have been correlated mental health issues and disease. Can you elaborate on that at all?
CPGP El Nino is a natural phenomenon that occurs periodically when warm ocean water temperatures develop off the Pacific coast of South America affecting weather patterns globally. It is important to distinguish between a natural variability and climate change due to human impact. We don’t know very well what’s going to happen with the frequency of El Nino events as the climate further warms. This is under current research. These natural fluctuations have always been occurring in the climate system, and they will continue to occur under human induced global warming. An important and unresolved question is indeed whether theses events will be more or less frequent in the future. With respects to health effects: climate variability definitely affects health in many different ways. We know pretty well the climate patterns that affect certain diseases, and we know that some of these patterns are going to be more frequent. For example heat waves: it is clear that globally the number of days with maximum temperatures is increasing. The projections are towards a further increase if we still continue business as usual with regard to carbon emissions. Extreme heat is connected to heat strokes and increased air pollution which has a strong impact on respiratory health. Increased temperature promotes ozone, which is a component of the smog in the cities. Also, enhanced drought conditions involve higher risk of wildfires, a threat to human life that also affects respiratory illnesses through the release of smoke particles.
After disasters such as Katrina, we have seen the short-term and the longer-term effects of weather extremes on mental health–people suffering from anxiety and people with preconditions being potentially more vulnerable to extreme events. Adaptation and response measures will be very important. For example, efficient air conditioning systems during heat waves, early warning systems, especially for the elderly and the poor that do not have access or the means for necessary measures to endure these kind of episodes. Also you know, many infrastructures have been designed for a past climate. We’re not heading towards climate change, we’re already there and this is going to put pressure on our current infrastructures. We need to improve our infrastructures, our response system, our information systems and education, and at the same time, we need to reduce emissions of greenhouse gases to prevent some of the damages in the future.
GN We have discussed how people can feel overwhelmed and distressed by climate change information and what it means to our way of life. However, people need the facts so they can help activate positive solutions. Interrelating the issues and challenges of climate change to education is extremely important, and we know that opportunities can come out of problems. We are launching a green economy.
CPGP Yes, definitely education, and businesses need to take into account this environmental threat, but we need—at the same time—to promote a green economy. The economy needs measures so that we can move from the coal and fossil fuel paradigm. It is not reasonable that producing energy with fossil fuels is cheaper than producing energy with other cleaner options. There is no way to go towards a green economy if we don’t acknowledge the environmental costs. Fossil fuels have a future environmental cost that is not taken into account, it’s not only the cost of production, transportation, distribution, it has an environmental cost which is huge and it’s global and it’s …
GN A health cost.
CPGP A health cost. That we’re seeing already. So that has to be included in the cost. I don’t know the specific ways of doing that. There are many experts proposing ideas, but if we want to move the economy towards greener options…I mean, being green has to be better from an economic standpoint because we are in an economy that works like that. We cannot just expect that the economy is going to move towards the green direction if it’s not efficient from an economical point of view. So the Government needs to decidedly regulate that. We need to establish the basic rules. It’s not about going against freedom, no; it’s not about that. It’s about setting fair rules to promote the options that we value as a society.
GN There definitely are many economists who are looking at our valuation system and searching for a way to create formulas that will account for the true worth of the environmental stake. We’ve talked before about the importance of promoting leaders that will move us to a green economy and the need for a global political will to move the situation–the resolution–to some of these problems in the right direction. How do you personally see your action, your future path in relationship to what you now know? How do you think things might unfold?
CPGP For now, I want to be a scientist. However, we climate scientists need to get out of the offices and the labs. We have to talk about what we know and in a very consistent and solid way. You know, climate communication is very important. We’re human. We don’t perceive climate, we perceive weather, and weather is the noise of the climate. Climate is the trend. Maybe some elderly people can perceive those trends, they can see that when they were young, things were different, but the youngest people living in urban areas with less contact with nature and subject to many other things in life…it’s difficult for them to perceive climate change. You perceive weather. You perceive the daily changes in temperature. So climate communication is important and we need to come up with better ways to communicate climate science. It’s a challenge. And many social scientists are looking at it.
GN So important. I’ve observed the emergence of this call to action for scientists at several big science and social science meetings. It’s no longer working for scientists to only present their findings to leaders. They have to go directly to the public in order to move the situation along. Science must be social.
CPGP Absolutely. We have to go to the public but also we have to be aware of the mechanisms in place. We all have a mental model and we need to be aware of it. There is the confirmation bias—people are going to read information and are going to discard information that is not in line with their own priorities, ideology, or beliefs, so we need innovative methods to address this issue. When we communicate, we need to understand those processes. We, scientists, do not communicate beliefs. It's about evidence and proof. While we try as much as we can to avoid confirmation biases in our research, we should also take that into account when communicating science.
View Dr. Carlos Pérez García-Pando speaking on Climate Change and its Challenge
Here are resources that he recommends to stay up-to-date on climate change and its impacts on the environment:
National Climate Assessment: http://nca2014.globalchange.gov/
NASA Climate: http://climate.nasa.gov
Earth Institute: http://www.earthinstitute.columbia.edu/sections/view/9
EPA climate change: http://www.epa.gov/climatechange/
CDC climate change: http://www.cdc.gov/climateandhealth/
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