Google logo is seen at the Google headquarters in Brussels. (Virginia Mayo/AP)

In a year in which the world will focus heavily on climate change, its top search provider is relaunching a popular feature — Google Trends — and providing a special data visualization to capture how people living in 20 of the world’s major cities search for information about “global warming” and related terms.

The interactive, created by data visualization firm Pitch Interactive working with Google’s News Lab, displays search volumes in 20 major cities across the years from 2004 through 2015, for the terms “global warming,” “energy,” “oceans,” “drinking water,” and other environmentally focused words and phrases. It also shows what the most popular searches in each city  were.

The interactive works best on most modern browsers. Here’s a video of how it works:

“We wanted to show how this big issue looks when viewed through the lens of Google search data. Google data is so big — there are over 3 billion searches a day — that our challenge was how to make those huge numbers meaningful,” said Simon Rogers, data editor of the News Lab.

The resulting data show that the Indian megacity of New Delhi was No. 1 of the 20 large cities, for “global warming” searches. The top three searches in the city were: “What is Global Warming?” “How to stop global warming?” and “How is global warming a threat to life on earth?”

The gigantic volume of data were normalized – what that means, said Rogers, is that  cities ranked higher if a higher proportion of the total searchers from that city were about “global warming” (or other environmental topics). Furthermore, the Google Knowledge Graph was employed to ensure that all global warming related searches were recognized as such even if they used different words, like (in an example from Google) “polar caps melting” — even as false positives were thrown out.

One notable thing about the resulting data is that many of the major cities — including New York (No. 7) and London (No. 10), but also Delhi (No. 1) and Hong Kong (No. 9) — showed peaks in “global warming” searches in the 2006-2007 range. In other words, the climate issue seems to have been at its peak a while back in these places, in the days of Al Gore’s “An Inconvenient Truth” and the awarding of the Nobel Peace Prize to Gore and the United Nations’ Intergovernmental Panel on Climate Change.

The world is warming, and 2014 was the hottest year on record, so you might think levels of concern about the problem should be higher now than they were in 2006-2007. However, overall awareness may not have actually tracked with the problem’s mounting seriousness and urgency.

It’s unclear is whether 2015 — a year featuring Pope Francis’s massively anticipated environmental encyclical and the globally crucial Paris meeting to set new global emissions caps — will suffice to raise overall attention to the subject above its previous historic high levels.

The most recent data also show how the emergence of major environmental problems lead to changes in search behavior — thus, in 2014-2105, drought-plagued Sao Paulo saw a dramatic spike in searches for “drinking water.”

In their top three searches, people in Sao Paulo asked the following questions: “What is the percentage of freshwater on the planet?”, “How to get clean water?”, and — signaling perhaps most of all the city’s struggle — “How to make ocean water into drinking water?”

You can visit the interactive to get much more data here.

Also in Energy & Environment:

Why green spaces are good for your kid’s brain

How the climate debate keeps us from just letting science be science

Study shows climate change’s surprising toll on early dinosaurs

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