So, if you're living in the UK, surely an apple,
imported from New Zealand has a bigger carbon footprint
than one grown at home.
Not necessarily, because if you buy that British apple in, say,
July, typically it will have been
sitting in cold storage for nine months.
The resulting carbon emissions will be greater
than if it had been shipped from the other side of the world.
Transport can play a significant role.
The fact is that every stage of a food's lifecycle
contribute to its overall carbon footprint.
These can range from the fuel and pesticides used
in production to processing and packaging,
or the emissions created if it's eventually
thrown away by the consumer.
When it comes to transport, shipping accounts for about 60
per cent of global food miles, while air travel makes up
less than 1 per cent.
Air transport only tends to be used
for highly perishable goods, such as asparagus,
green beans, and berries.
But it boosts a food's emissions significantly.
For example, green beans air freighted to the Netherlands
from Kenya have a much larger carbon footprint
than those grown locally or shipped from Morocco.
Now, as consumer awareness rises the move toward carbon
labelling is gathering momentum.
Quorn Foods is aiming to put carbon emission labels on 30
of its bestselling products this year,
and other major food companies could follow suit,
including Nestlé and Premier Foods.
However, it's not a simple task.
UK supermarket chain Tesco abandoned carbon labelling
after a few years in 2012, claiming it took a minimum
of several months work to calculate the footprint of each
product.
But today, thanks to technology such
as smart sensors and big-data tools,
there is much more information available,
and measuring a food's carbon emissions is becoming easier.
Eventually, we may actually be able to accurately judge
our shopping on its true carbon footprint,
wherever it's come from.