This week, representatives of 195 nations and the 28 member states of the European Union are meeting in Paris to try to put together the first global agreement to curb carbon dioxide emissions. Among those nations, some are already doing much better than others.
One of the puzzles of atmospheric chemistry is why carbon dioxide concentrations in our atmosphere aren’t rising even faster. Our activities emit some 37 billion metric tons of carbon dioxide each year. About 45% stays in the atmosphere, 25% is taken up by the oceans. The rest is a bit of a mystery.
We have talked about food waste before. It is a big problem in this country: some 31% of our food supply is wasted, more than 130 billion pounds a year. Food waste makes up 21% of solid waste in municipal landfills, which means that it accounts for the bulk of landfill methane emissions. Methane is more than 20 times more effective as a greenhouse gas than carbon dioxide, and landfills are a major source of it.
Coal is the most important energy source for the Chinese economy and in a number of other places around the world. It is still the largest source of electricity in the US. It is also one of the main reasons that greenhouse gas emissions continue to increase despite worldwide technological progress and the expansion of renewable energy. New coal plants are still planned in many places and such plants will emit carbon dioxide for decades.
The Joint Center for Artificial Photosynthesis was established at Caltech and its partner institutions in 2010 with one main goal: to find a cost-effective way to produce fuels using only sunlight, water and carbon dioxide. The natural process of photosynthesis in plants accomplishes exactly the same thing. As a result, such a solar fuel generation system is generally described as an artificial leaf.
It may seem like we are constantly talking about toxic algal blooms – in the ocean, in lakes, and in rivers. That’s because they are occurring with greater frequency and are posing a greater threat than they have in the past.
Once, the constancy of seawater was taken for granted. Now, as we see evidence of increasing concentrations of mercury in seawater, it is becoming obvious that global pollution is taxing the dilution capacity of the seas. There is also good evidence that the ocean is acidifying.