What would be considered an observable indication of global warning

-- 100-year average temperature rising
-- percentage of carbon-dioxide in the atmosphere rising
-- average high temperatures for a year rising
-- temperatures of the oceans rising
-- severe weather events happening more often
-- large, energetic storms happening more often
-- glaciers shrinking
-- polar ice shrinkikng
-- habitat for animals in polar zones shrinking
-- temperate-zone trees and plants spreading toward the poles
-- growing seasons getting longer
-- dry areas getting more heavy rain events
-- rainy areas having more extended dry periods

Note:
Everything on this list IS being observed.
You can argue about what's causing it, but
you can no longer claim that it's not happening.

Since wxyz is 4, halfof that would be 2.