Climate scientists, who have warned of the dangers of global warming for decades, have found some countries to listen. This week, representatives of more than 50 nations gathered in Santa Marta, Colombia, at what was billed as the first global summit on phasing out fossil fuels. One of the first orders of business was to launch a panel of scientists that will advise those countries on how to shift to clean energy. 'Here, you have a coalition of governments that decided they actually want to be informed by the science,' says Margaretha Wewerinke-Singh, an international climate-change law specialist at the University of Amsterdam. The landmark meeting, which began on 24 April and concluded yesterday, was proposed during last year's United Nations COP30 climate summit in Belem, Brazil. Oil-producing nations such as Saudi Arabia reportedly opposed attempts at that gathering to create a road map to cut the use of fossil fuels, which are the main source of global greenhouse-gas emissions and the largest contributor to climate change....

We are what we eat. And in the ocean, most life-forms source their food from phytoplankton. These microscopic, plant-like algae are the primary food source for krill, sea snails, some small fish, and jellyfish, which in turn feed larger marine animals that are prey for the ocean's top predators, including humans. In an open-access study appearing today in the journal Nature Climate Change, the team reports that as sea surface temperatures rise over the next century, phytoplankton in polar regions will adapt to be less rich in proteins, heavier in carbohydrates, and lower in nutrients overall. The conclusions are based on results from the team's new model, which simulates the composition of phytoplankton in response to changes in ocean temperature, circulation, and sea ice coverage. In a scenario in which humans continue to emit greenhouse gases through the year 2100, the team found that changing ocean conditions, particularly in the polar regions, will shift phytoplankton's balance of proteins to carbohydrates and lipids by approximately 20 percent. The researchers analyzed observations from the past several decades, and already have found a signature of this change in the real world....

Because the past three years have shattered temperature records (see 'Temperature boost'), researchers have been exploring whether global warming is accelerating, and if so, why. Many scientists agree that the rate at which it is increasing has picked up. This is mainly because of a reduction in air pollution following the introduction of fuel regulations for international shipping (which has resulted in fewer pollutant particles that reflect sunlight into space and seed insulating clouds). In the data, 'you can practically see by eye that it has accelerated', says Stefan Rahmstorf, a climate scientist at the Potsdam Institute for Climate Impact Research in Germany. Rahmstorf and Grant Foster, a statistician in Orono, Maine, say they have the strongest evidence yet that global warming has sped up, to a rate of around 0.35 'C per decade. That's faster than some other estimates2. But, the pair say their analysis captures a more accurate picture because of the way it accounts for and removes the effects of natural factors, such as weather events and volcanic eruptions, that cause climate fluctuations. The study was published today in Geophysical Research Letters1....

My first post here was a sketch of my view of the consequences of climate change, that there are both good and bad effects and we do not know enough to say whether the net effects is positive or negative. It now occurs to me that I can say a little more. There are two approaches to answering that question. The first is to ask whether there are general reasons to expect climate change along the predicted lines, a gradual increase in average temperatures due mainly to increased CO2 in the atmosphere, to have net negative effects. The second is to look at specific externalities, make some rough estimate of their size, and add them up. That is a short run effect, relevant over decades but not centuries. Over centuries people can adjust what crops they grow and how they grow them, where they live, how they heat and insulate their houses. More warmth is generally a good thing when you are cold, a bad thing when you are hot. Due to the physics of the greenhouse effect, it warms cold times and places more than hot, raises the temperature of winter more than summer, of the polar regions more than the equator....