We aren't worried about the "planet's" temperature. Our concern is with the thin layer of the planet's surface in which we live - about equivalent to the layer of water on a wet apple, or the morning frost on the roof of a car. It's fairly easy to alter the temperature of, say, the upper 10 meters of the soil and water along with the 10 kilometers of gas above it. Just slightly changing the balance of absorption and emission of radiant energy from the sun in that layer will do it, for example. It does take some effort, but we have been putting the work in and we have significant achievement to show for that work.
It is raining in central Minnesota during the month of January again this year, as of now - January 16th. The traditional frequency of measurable rainfall here in January was - since the European arrival and weather records, mid 1800s - one year in seven. This was due to nighttime temperature drops - IR vanishing out through clear dry air - far below freezing. Starting in the mid 1990s, things changed. It has now rained in January for something in the neighborhood of twenty consecutive years. In addition, the central time of severe cold has moved - traditionally, the coldest time of the year was a two week span sometime around January 20th, and the coldest night would be found within it. This year, and very commonly of recent years, that has not happened - the coldest day coming in December as often as not, and the coldest weeks shifted as well. The current forecast for January 20th in my town is a nighttime low above freezing, a high over 40F, and a bracketing week of thaw and fog and rain. Most of the difference appears to be the diminution of the nighttime temperature drops, leaving the air much wetter as well as warmer each morning.
IMO, Presumed by most believers in GW, but NOT demonstrated to be historically 'man-made'. If I may add . . .
It rained again this past January, in central Minnesota, for something like 20, 21 consecutive years now (lost count) - this phase change in the weather appears to be the new normal. Meanwhile, farther north: https://nsidc.org/data/seaice_index/images/daily_images/N_iqr_timeseries.png http://nsidc.org/arcticseaicenews/files/1999/03/asina_N_iqr_timeseries.png
