Maybe take a look inside the 2010 theme that comes packaged with WP, index.php shows a call to a loop file: <?php get_template_part( 'loop', 'index' ); ?> so you could (well this is how i would do it, cos i think it looks neater, but you could use multiple loops) create 2 new loop files for example they could be called loop-economy.php and loop-enviroment.php both of these loops set to call only posts from there respective categories and then use:
<?php get_template_part( 'loop', 'economy' ); ?>
where you want the economy posts to show in your template and then use:
<?php get_template_part( 'loop', 'environment' ); ?>
where you want the environment posts to show in your template