Human actions are changing the World’s biophysical and ecological systems. These systems are intrinsic to life processes and fundamental to human health, and their disruption and scarcity have made it more difficult to deal with health disparities. In fact, if environmental destruction continues, we will not achieve the UN Millennium Development Goals. Health professionals have a significant contributing role in preventing and mitigating the health effects of global environmental change.
Human health has always been influenced by climate and weather. Changes in climate & climate variability especially change in the extremes of weather, affect the environment that provides us with clean air, food, water, shelter, and protection. Climate change, along with other natural and man-made health stresses, threatens human health and well-being in many ways.
Some of these health effects are already being experienced globally. Given that the effects of climate change are projected to increase over the next century, some current health hazards shall intensify and new health hazards may emerge. Our understandings of climate change and its impact on human health shall be useful in reducing the amount of future climate change, priorities for protecting public health, can make suggestions, and help identify research needs.
Our Changing Climate
Observed Climate Change
The fact that the Earth has warmed up in the last century, is uneven. Many observations of air and sea temperatures, sea levels, and snow and ice have shown these changes unprecedentedly over the centuries. Human impact has been the major cause of this observed warming. A few years ago National Climate Assessment has found that rising temperatures, resulting in an increase in the frequency or intensity of some extreme weather events, rising sea levels, and melting snow and ice are already disrupting people’s lives, and are alarming for the global economy.
The concepts of climate and weather are often confused. Weather is the state of the atmosphere at any time and place. The weather pattern varies greatly from year to year, and from region to region. Familiar aspects of the weather include temperature, rainfall, clouds, and wind that people experience throughout the day. Climate is the average weather condition that persists for several decades or longer. Although the weather can change in minutes or hours, observations from decades to centuries or longer are needed to identify changes in climate. Climate change involves changes in rainfall as well as shifts in precipitation, risks of certain types of severe weather events, and other characteristics of the climate system, along with increases and decreases in temperature.
Projected Climate Change
Estimates of future climate conditions are based on the results of climate models – sophisticated computer programs that simulate the behavior of the Earth’s climate system. These climate models are used to describe how the climate system is expected to change under different possible scenarios. These scenarios describe future changes in atmospheric greenhouse gas concentrations, land use, other human impacts on climate, and natural factors. The most recent set of coordinated climate model simulations uses a set of scenarios called representative concentration paths (RCPs), which describe four possible trajectories in greenhouse gas concentrations. Actual future greenhouse gas concentrations, and the resulting amounts of future climate change, will still largely be determined by the choices that society makes about emissions.
Our Changing Health
To understand how climate change creates or exacerbates health problems, the health effects of climate change must be assessed along with the current state and trends observed in a summarized array of health conditions. Furthermore, because hygienic status, socioeconomic status, and standard of living all contribute to vulnerability to climate-related and meteorological health effects, assessment of climate change health impacts should be informed by anticipated changes in these factors.
In cases where people’s health or socioeconomic status is deteriorating, climate change can increase the health burden associated with those deteriorating trends. Conversely, in cases where people’s health or socioeconomic status is improving, the effect of climate change may be to slow or reduce this improvement. Where scientific understanding allows the status quo, the inclusion of projected trends in health and socioeconomic conditions into models of climate change impacts health. At the same time, these interactions between non-climatic factors and climate change impacts can provide useful insights.