It depends what you mean by easy. Your carbon footprint doesn't just depend on what you EAT. It depends on what you do with the rest of your life. If you own five gas guzzling cars, don't have any insulation in your house, and fly to Bali three times a year then maybe you need to address these issues first. So my first response to this question is 'no'.
If you're serious about reducing your carbon footprint you need to have some idea of what your carbon emissions are at the moment. Find a carbon calculator on the Internet. There are lots to choose from. Here's a household one from Participant Media. You type in some information about your home, your energy use, your lifestyle and food choices and it does the sums for you. If you need to you can also get hold of one which measures emissions in your business premises.
If you get this far - you're building up a picture of which activities and purchases in your life produce the most carbon. That's going to help you in deciding where to start to reduce your emissions. Now you can start PRIORITISING. That's important. Saving energy and staying warm might be a priority for you. So you might want to put tackle draughtproofing in your home even before you start changing your food choices.
Becoming a vegetarian might indeed be one of your options though. We know there are lots of good reasons for taking this step. Not least the arguments about meat production and cruelty to animals. But as far as your emissions are concerned, be careful. If you're buying imported fruit and vegetables that have been shipped by air half-way across the planet you're probably not going to be doing much to slow down Climate Change.
Also, let's face it - it's sometimes really hard to make big changes in your life. So make the issues person-sized instead. Take a small step. Instead of doing away with meat altogether together, can you start eating LESS of it? Can you buy local, organically reared meat with a high standard of welfare? I'm quite a good cook but I love the taste of organic meat. So I wouldn't find it easy to make the switch.
What other options are there? Why not join me as a member of the world wide community of kitchen gardeners. It's not so difficult to teach yourself how to grow your own fruit and vegetables - in your own backyard.Then you can save food miles and carbon emissions without giving up meat entirely. Keeps us fit, reduces carbon emissions and saves money too. Once you savour the fresh taste of your home produced organic fruit and vegetables you may find yourself becoming vegetarian anyway!