| 英文摘要: | The slowdown in Earth's surface temperature increase has made headlines worldwide — but mainly to dismiss climate science. Man-made climate change has been in the news for many years. Previously the message presented to the public was clear: climate change is global warming and that means the temperatures are going to rise unless we do something. This claim seemed to be supported by measurements of continuous increases of atmospheric CO2 — at a rate not seen before in the historical record — and associated temperature increases. Additionally, projections from climate models seemed to confirm that this was the new normal. But does the public understand how climate models work? The projections from models are presented without much additional information on how they were obtained. A model is a simplified representation of the Earth's climate system based on knowledge of its various components — physical, biological and chemical processes — and their interactions and feedbacks. A projection of future climate can be made by applying a selected scenario of anthropogenic emissions (and therefore concentrations) or radiative forcing, which is a possible representation of what will happen. The outcome will depend on the scenario and model used as well as the initial conditions. Projections are reported from a number of runs, an ensemble, to capture the most likely future climate. Models for climate change projection using emissions scenarios work best by forecasting over the longer term. But most of us think in the here and now, so the message on climate change might have been heard on a different timescale from what the scientists intended. To complicate things even more, in the past decade the climate hasn't warmed at the rate projected, and evidence of the slowdown in temperature rise has sparked a lively scientific and public debate, as highlighted this month by a collection of articles in our Focus 'Recent slowdown in global warming'.
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