climate change

The most common use given to this expression refers to the changes taking place in the Earth's climate as a consequence - to a large extent - of human activities linked to the emission into the atmosphere of greenhouse gases, coming from the massive burning of fossil fuels. The observed global warming is the clearest manifestation of current (implicitly anthropogenic) climate change. In a broader sense, the term refers to any form of climatic inconstancy, regardless of its physical causes. Bearing in mind that the Earth's climate is changeable by nature, when statistically significant trends are detected within its natural variability (over sufficiently long periods of time), one can properly speak of climate change. Throughout the history of the Earth many such changes have occurred, of different sign and magnitude, although the singularity of the current one is that it cannot be attributed exclusively to natural causes.