Not necessarily, because if you buy that British apple in, say, July, typically, it'll 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% of global food miles, while air travel makes up less than 1%.

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 technologies 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.