It feels auspicious that my first day of blogging is happening on Blog Action Day, an annual event which unites the world's bloggers in posting about the same issue on the same day. Blog Action Day focuses attention on an issue of global importance, with the aim of sparking discussion and action. This year’s theme is climate change.

Now …..what does that have to do with health?

I used to think of climate change as an environmental issue – saving forests, keeping ices floes from melting, and “protecting the Earth” in a nebulous way. But more and more, I’m realizing that climate change is really a health issue.

Climate variability already causes death and disease through heat waves, floods and droughts. Climate change makes these “natural” disasters more frequent and severe. It also increases sickness and death from major vector-borne diseases like malaria and dengue fever. It leads to less reliable rainfalls; less rain or rain at the wrong time means people don’t have proper access to drinking water or water for their crops. People weakened by hunger are more vulnerable to diseases, so the effects of climate change are compounded.

Climate change is also a social justice issue, because it exacerbates existing inequities. According to the WHO, “the impacts of climate on human health will not be evenly distributed around the world. Developing country populations, particularly in small island states, arid and high mountain zones, and in densely populated coastal areas, are considered to be particularly vulnerable.”

What can we do? We can get informed: Read 10 facts on climate change and health, from the WHO. We can also act. For starters, sign a petition asking world leaders to enact a fair, ambitious, and binding climate change agreement when they meet in Copenhagen for the United Nations Framework Convention on Climate Change talks this December.