Until recent decades, physical activity, a balanced diet, proper hygiene, and avoiding harmful habits almost completely ensured the most precious and priceless gift of humanity, a gift that even money can't buy: health.
However, also until recent decades, the factor that more and more violently affects this fragile prescription’s effectiveness was not known: climate change.
We've all heard about it, and we know what it's about: the reason that polar bears balance on blocks of ice, the uncomfortable truth of Al Gore’s documentary, and that which allows people in some parts of the world to fry eggs on asphalt.
But how does climate change affect me? I live in the city, far away from the coasts and with air conditioning, – so what if the temperature is a little warmer than usual? Isn't that what sunblock is for?
According to the World Health Organization (WHO), it is estimated that between 2030 and 2050 climate change will cause some 250,000 additional deaths each year due to malnutrition, malaria, diarrhea, and heat stress in the most vulnerable regions.
"Many of the most deadly diseases, such as diarrhea, malnutrition, malaria, and dengue fever are very sensitive to climate, and are expected to be exacerbated by climate change," the WHO has stated.
Human activity, particularly the burning of fossil fuels, is releasing sufficient amounts of CO2 and greenhouse gases to raise the earth's temperature to critical levels, altering the global climate and therefore human health.
These changes in climate, from an increase since the industrial revolution of more than 30% in atmospheric carbon dioxide concentrations, bring serious risks and causes heat waves and infectious diseases.
"The Point of No Return: Climate Change Nightmares Are Already Here" was the title last week of a Rolling Stones article, in which 2015 is marked as the year historians might use for a reference to talk about the moment when the worst consequences of human caused climate change began to beat us.
According to WHO data, in the twentieth century’s last decade weather-related natural disasters caused approximately 600,000 deaths worldwide, of which 95% were in the poorest countries.
If this is added to water shortages, rising death rates from heart and respiratory diseases due to heat waves, and breathing problems cause by air pollution, reality screams at us that climate change already is not about hot or cold. This is about life and death.
Humanity is facing the biggest challenge it has ever faced. World leaders are calling for action before it's too late. "Time is running out and paying the bill will be more expensive," said Ban Ki Moon at the Climate Change Conference in Lima last December.
The top leader of the Catholic Church joined the call and did something never done before: issued the first and most important official religious text urging the faithful, politicians, and citizens of the world to make a change to avoid the worst consequences of the so-called great collective suicide.
"The human environment and natural environment are falling apart together, and we cannot adequately address environmental degradation if we do no pay attention to causes that have to do with human and social degradation," said Pope Francis in his encyclical Laudato Sí.
The eyes of the world will be in Paris at the UNFCCC COP21 this December, where leaders of the world must sign a global climate agreement to prevent global temperatures from increasing to catastrophic levels. Millions of lives will depend on the political decisions taken – or not – during COP21. Will the negotiators respond to the urgent and clear call for sanity?
Follow Lucía Vásquez on Twitter @luvasquezv