  We propose a non-steady state model of the global temperature change. The
model describes Earth's surface temperature dynamics under main climate
forcing. The equations were derived from basic physical relationships and
detailed assessment of the numeric parameters used in the model. It shows an
accurate fit with observed changes in the surface mean annual temperature (MAT)
for the past 116 years. Using our model, we analyze the future global
temperature change under scenarios of drastic reductions of
CO\textsubscript{2}. The presence of non-linear feed-backs in the model
indicates on the possibility of exceeding two degrees threshold even under the
carbon dioxide drastic reduction scenario. We discuss the risks associated with
such warming and evaluate possible benefits of developing
CO\textsubscript{2}-absorbing deciduous tree plantations in the boreal zone of
Northern Hemisphere.
