Climate Signals Detected in Global Weather


Searched for and found: climate researchers can now detect the fingerprint of global warming in daily weather observations at the global scale.

They are thus amending a long-​established paradigm: weather is not climate – but climate change can now be detected in daily weather.

In October this year, weather researchers in Utah measured the lowest temperature ever recorded in the month of October in the US (excluding Alaska): -37.1°C. The previous low-​temperature record for October was -35°C, and people wondered what had happened to climate change.

Until now, climate researchers have responded that climate is not the same thing as weather. Climate is what we expect in the long term, whereas weather is what we get in the short term – and since local weather conditions are highly variable, it can be very cold in one location for a short time despite long-​term global warming. In short, the variability of local weather masks long-​term trends in global climate.

Now, however, a group led by ETH professor Reto Knutti has conducted a new analysis of temperature measurements and models. The scientists concluded that the weather-​is-not-climate paradigm is no longer applicable in that form. According to the researchers, the climate signal – that is, the long-​term warming trend – can actually be discerned in daily weather data, such as surface air temperature and humidity, provided that global spatial patterns are taken into account.

Continue reading at ETH Zurich

Image via ETH Zurich