Direct impacts of climate on human health occur when the human body is physically stressed or injured immediately by some element of the climate system.
Examples of direct impacts include:
- extreme heat
- extreme cold
- other extreme weather events
Remembering that we're looking at the direct impacts on human health right now, we're thinking about the immediate impact events such as hurricanes, wildfires, droughts, and floods have on people's health. But how many people are affected by these various extreme weather events?
In 2015, the Centre for Research on the Epidemiology of Disasters (CRED) and the UN's Office for Disaster Risk Reduction (UNISDR) published The Human Cost of Weather Related Disasters 1995-2015. The timing of this report wasn't accidental - it was intended to help inform the urgency of the then-upcoming Paris climate negotiations producing meaningful targets for GHG mitigation. The two infographics below show the numbers of people affected and killed by weather-related disasters in 1995-2015.
- (Insert screeching brake sound.) Ok, but each of these types of extreme weather events was occurring before anthropogenic climate change. Yes! True. But, current understanding of the science strongly suggests that these types of events will increase in both frequency and intensity in a changing climate. So, certainly, not every person affected by a hurricane is someone who wouldn't have experienced that hurricane in the absence of climate change - that's not what we're talking about here. Instead, we're trying to understand that climate change is making these events worse in several dimensions, and this will in turn have bigger consequences for more people, and therefore we need to understand the magnitude of the potential problem and looking at the totality of people affected helps us do just that.