Not sure but try this:
function get_years ($taxonomies, $args){
$output = array();
$hlterms = get_terms($taxonomies, $args);
foreach($hlterms as $term){
$term_taxonomy = $term->year;
array_push($output, $term->name);
} return $output;
}
$taxonomies = array ('year');
$args = array ('hide_empty'=>true);
$year = get_years($taxonomies, $args);
echo min($year);