about why I believe that big data is good data.

And I am going to explain why I think that

by talking through another passion of mine, which is cities.

but in 2008, we passed an important tipping point globally

than they do in rural environments across the world.

We have millions of people moving into cities across the world.

So that, by the time a majority of this audience is retirement age,

70% of the world's population will live in cities.

Cities are also proving slightly problematic.

They are the cornerstones of consumption.

They take up just 3% of the world's land surface area,

and yet they are responsible for 75% of global resource consumption.

So when we're thinking about sustainability,

Thirdly, cities are proving to be more powerful than ever.

We are seeing mayors to become pragmatic global leaders

willing to take on issues that nation states are struggling with.

They're also willing to collaborate, to come together,

and the compact of mayors at the recent UN Climate Summit in September

with all its challenges, and its opportunities,

we also have within the same generation an incredible shift,

When I think back to a time when I was home after school,

and a gentleman came to the door, a salesman,

that you would buy, and you would have on your bookshelf,

and you would refer to them when you were doing your homework.

(Laughter) and it's like-- It's life before Google!

but, you know, I don't consider myself to be that old.

And this is not just about how the Internet has also transformed

the way we search for information, the way we educate ourselves.

This is also about the fact that all manner of appliances and devices

are increasingly online, increasingly connected,

there will be double the number of devices online

these tiny sensors, these smart TVs, these connected cars,

they are each creating a tiny, continuous vapor trail.

And it's the aggregation of these vapor trails into a common place

we have the rise of the city, and we have the explosion of big data,

it's when you bring these two things together,

it's at this point of convergence I think things get really interesting.

And that's the exact field of work that I am in.

you have these millions of data streams being generated,

New York generates a terabyte of data a day.

from energy meters, from people's mobile phones,

and its the ability to bring together these data streams

that allows you to better sense the city.

To better understand its metabolism in real time.

To better match supply with demand for resources.

that we use to better design and run our cities in the future,

So perhaps I could give you a couple of examples.

The use of acoustic sensors which are calibrated to detect gun shots

have shown that, while people assume that people would report a gun shot heard

the reality was actually people only reported it around 10% of the time.

to be able to understand in which neighborhoods,

at which times of the night or day these things were occurring

helps the police to deploy precious resources.

A second, completely different example, and this time it's really interesting,

because they're using the public to actually help gather their big data set

they are actually providing citizens with small umbrellas

which have the ability to detect the level of rain fall at any given time.

And combined with a small app on citizen's phones,

they are then becoming the crowdsource sensing

that enables the city to understand the real-time propensity for flood risk.

and perhaps if I'd asked you when you walked into the auditorium this afternoon,

what do you think of, when you think of big data?

would have connotations of Google or Facebook.

We might presume this new commodity is something

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