The effects of the global changes related to rapid modification in climate patterns are so heterogeneous, complex and vast that understanding all climate-change related environmental and socio-economical effects is one of the largest efforts in the science world. A rapidly changing climate will undoubtedly have consequences on human well-being and health: people will be forced to adapt to new temperature averages, new weather extremes, as well as different weather and climate patterns (the length of seasons and pollen seasons, higher rain-intensity, drought).
Although climate patterns have previously been relatively stable, in the next 50 years they are likely to change at an increasing speed. The major public health organizations of the world say that climate change is a critical public health problem. Climate change makes many existing diseases and conditions worse, and may also contribute to the introduction of new pests and pathogens into new regions or communities. As the planet warms, oceans expand, sea levels rise, floods and droughts become more frequent and intense, and heat waves and hurricanes become more severe. The most vulnerable people – children, the elderly, the poor, and those with underlying health conditions – are at increased health risks due to climate change. Furthermore, our health care infrastructure will undergo new increasing stress. Science data show that action must be taken.
CMCC discussed the impact of climate change on global health with George Luber, Associate Director for Climate and Health at the Centers for Disease Control and Prevention (CDC), a national public health institute of the United States, headquartered in Druid Hills, DeKalb County, Georgia. The CDC is a federal agency under the Department of Health and Human Services. It was established in 2006 as several scientists had recognized that there was a need to prepare for the inevitability of climate change, as well as the impact it would likely have on the health of US residents and the world population in general. In 2009, the program took center stage, seeking to identify the populations most vulnerable to these impacts, to anticipate future trends, and to ensure that systems are in place to detect and respond to emerging health threats, and take steps to ensure that these health risks can be managed now and in the future.
Increasing evidence shows that climate change will have a relevant impact on our health with dire consequences in many states around the world.
Indeed there is good evidence behind the notion that climate change will drive an increase in injuries and deaths related to extreme weather, the redistribution of diseases, and many health outcomes are either directly or indirectly linked to changes in warmer weather. The manner in which health will be compromised through climate change can be summarized in three basic pathways.
First, there is an entire host of conditions that are related to environmental quality. World needs will increase as a result of the cumulative stress that climate change will put on these health outcomes. So, for example, we’ll have an increase in heat related deaths; an increase in bad air-quality days, an increase in the length of the pollen season, and stimulation through the increased carbon dioxide of pollen levels; and also an increase in the number, frequency and duration of wildfire deaths – we have interesting evidence from New Mexico and from other parts of the world.
Do we have to expect new exposures?
No, we are already dealing with these things, but the magnitude of their effects will change.
The CDC document states that the second pathway in which climate change will impact health is through the probability of complex emergencies.
Complex emergencies happen where the coping capacity of a location is exceeded by either the increased frequency of an event – multiple hurricanes, one after another, hitting an area reducing its capacity, or by the sheer magnitude of the event. So category 2 and 3 storms now become category 4 or 5 storms, and the magnitude of those changes can overwhelm the capacity of the health department and other related agencies.
A collapse of emergency infrastructures.
What that sums up is the increase in the probability of multiple system failures. We are able to cope with a particular range of weather extremes. But once those are exceeded – look at Europe in 2003, look at Russia in 2010, look at Hurricane Sandy in the New York area – we are in trouble. So the magnitude of those effects of compounding impact through multiple system failures, either as power goes out, telecommunication goes out, or access to moving people from harm’s way is compromised.
What about the third emerging pattern?
This is the emergence of novel diseases as a result of a profoundly changed ecology.
It covers a wide range of conditions: novel disease emergence can be applied to mosquito-born, vector-born infectious diseases, as well as harmful algal bloom. We’re seeing a change in the distribution of these cyanobacteria, or blue-green algae: we are observing that algal blooms occur in fresh and marine water areas where they haven’t been found before.
Which strategies are the medical and the political world adopting to respond to climate-related health risks? Could you provide us with an insight of the United States according to the CDC? Are there dedicated research structures, collaboration with universities, or coordinated strategies with the World Health Organization (WHO)?
Yes to all of the above. Consider this: our program on climate and health was formally created in 2009.
So it’s fairly young.
Very young. It’s a new initiative in public health; it’s a new area of concentration that is convening people in a wide variety of areas from informatics and surveillance all the way to epidemiology studies that are trying to assess what the thresholds for these health effects are.
Given that, we collaborate with universities. We collaborate principally with health departments within the United States. Our job is to not only to identify the health risks and track them, but also to develop strategies to assess the risks that are apparent at an operational scale, in other words, at a smaller scale than at the national scale because the impacts that will be felt in Florida are going to be widely different from those felt in Maine, for example, in the North. So there has to be some capacity to assess what the climate change impacts will be, whether it’s temperature or precipitation or sea-level rise, and match that to the health profile within a particular jurisdiction to then forecast what those future challenges will be. And we do this in a very geographically specific way because we do understand that the impacts of climate change vary significantly by region, and so must the defense.
You collect data and elaborate scenarios: how will these results be implemented in the “real world”?
Our strategy is elaborated through a framework we have developed called B.R.A.C.E., an acronym for Building Resilience Against Climate Effects, and it’s an evidence-based process designed to lead to a health plan for climate change that takes into consideration current and future climatology. It takes into consideration current and future vulnerabilities to those changes in climatology; it also assesses current and future burdens that are related to those exposures. So there is an epidemiologic assessment component that is used to project the future healthcare related to these. And what that is supposed to do, is give us a sense of current and future trends, which can be matched to intervention that can protect the public.
So we determine, let’s say an area that has a current burden of heat-related illness, and it is supposed to increase in the future. We know that health departments can incorporate a number of different interventions that are designed to protect people’s health, for instance, seasonal preparedness and response activities such as putting in cooling shelters, or providing communication and messages to the vulnerable. It also extends into multi-seasonal preparedness to all levels of intervention and adaptation that are intended to reduce these exposures in the first place.
Let’s consider reducing the urban heat island effect, another critical area: knowing the impact, public health can inform decisions made in other sectors such as urban planning, transportation and energy use to help anticipate the ways in which health can be protected. CDD does not make policies itself, but distributes evidence that can be used to prioritize which intervention can have the most impact. The goal is to arrive at adaptation plans that prioritize interventions that are driven by health concerns.
Geo-data that match health-data and climate data seems to be key in your research and policies. Does GIS (geographical Information Systems) play a key role?
GIS is used in a couple of different ways, and one is to assess the difference in vulnerability to these impacts as a function of the vulnerability that a particular geography has. The coastal area, those that live within a 100-year flood plain, those that live within an urban heat island are more vulnerable to the exposures as a result of their particular geography. So we try to match the vulnerabilities of a place with the characteristics of the population and the context.
Populations have spatial attributes that confer particular protection or vulnerability: these range from the distribution of air-conditioning to the current health status of a community, their burden of chronic diseases (diabetes, cardiovascular diseases, respiratory diseases), even their diet. This is very important for understanding how well they’ll respond to extreme events. So we match those different types of vulnerabilities with current and projected exposures that are climate sensitive, or predicted to change the climate, and affect the level of vulnerability of a particular location.
We work with the health department to make that assessment. It’s important to develop capacity for these assessments to be done in many different places, and so our job is to provide technical guidance (including GIS) and support, and to also help build capacity in state and local health departments to permit them to make these assessments themselves.
With increasing temperature, heat is going to be a menace to people’s health. CDC says if current emissions hold steady, officials project that the number of victims in the US could increase to as high as 5,000 by 2050. The main victims tend to be mostly elderly people. Could heat waves, regardless of their length and strength be a future threat to larger amounts of the population?
There is evidence that it can be a serious threat currently. It is not only the elderly, it is also the very young, those with chronic diseases, as well as outdoor workers. We see a signal in some areas of the United States where our principal heat-related deaths are with working males, indicating a particular challenge to the workforce in the future.
Are new geographies of diseases emerging?
The distribution of diseases is related to more than just climate, especially infectious diseases. However, there are conditions that are more closely linked to climate conditions than others. For example, I mentioned harmful algal blooms. We have a type of marine algal bloom that is called Ciguatera fish poisoning, which is a marine toxin. It’s very closely tied to sea surface temperature as well as the degraded habitats of coral reefs, especially those that have experienced bleaching.
Now we also have a shifting distribution of Lyme disease in this country. This is a very important vector-born disease; I believe it is number 3 on our list of notifiable diseases in the US. Malaria and Dengue are interesting examples: there is increasing evidence that those geographies are changing, as you would expect with climate change, increasing in latitude as well as increasing its reach in altitude as those habitats become more suited. Much more work will need to be done on this, certainly to solidify the evidence, and more funding will be needed.
What is the current size of CDC activity related to climate change?
The size of the activity is not very large compared to other CDC programs, but the design of it is intended to be scalable. We have produced different publications and we have developed a policy (the B.R.A.C.E.) on this that engages states, cities and community leaders and builds a workforce that has the capacity to deal with this. We have a number of challenges, but I think our program reflects the maturity of the science and will grow as the evidence base grows and as our efforts bear fruit in building capacity in the state health department. We currently have sixteen states and two large cities. It is our hope that within a year we will be successful enough to expand to a national program, where we will fund and build capacity in all 50 states.
What is your current budget?
Right around eight million US dollars.
Building a global information network is key. How closely do you collaborate with the World Health Organization?
We collaborate frequently with the WHO, with our colleagues at PATHO, and also with our colleagues at Health Canada, for example. We share our ideas and we consult with each other for best practices and best strategies for doing a number of things – from communicating the risks, to assessing vulnerability, etc.
Our efforts are informed by the efforts of others, and our engagement with international activities expands beyond that. We’re a member of the Inter-governmental Panel on climate change developing the latest methodology and strategy to identify key risks, key vulnerabilities, interactions between multiple systems etc. We are very active in a number of forums that are engaged in this. So we are not, and certainly do not pretend to be inventing anything on our own. It is all a result of collaborating with other leaders in the fields.
For health that includes the European CDC, the CDC in Stockholm; the World Health Organization, especially the European office of the WHO headquarters in Geneva. Still a lot more has to be done.
(Interview by Emanuele Bompan)