Is climate change a vicious circle?
There are indeed a lot of positive feedback mechanisms, i.e. a warm climate leads to a warmer climate. From this Wikipedia article, they are:

Carbon cycle feedbacks
Cloud feedback
Gas release
Ice-albedo feedback
Water vapor feedback

However, there are also a few negative feedbacks (same source):

Blackbody radiation
Carbon cycle
Lapse rate
Impacts on humans

Now the question is: what is the net budget between positive and negative feedbacks? To assess this, climatologists use some metrics, the main ones being &quot;transient climate response&quot; (TCR) and &quot;equilibrium climate sensitivity&quot; (ECS). From Knutti et al. (2017):

TCR is defined as the global mean surface warming at the time of
doubling of CO$_2$ in an idealized 1% yr$^{−1}$ CO$_2$ increase
experiment, but is more generally quantifying warming in response to a
changing forcing prior to the deep ocean being in equilibrium with the
forcing. Based on state-of-the-art climate models, and instrumentally
recorded warming in response to CO$_2$ and other anthropogenic and
natural forcings, the Intergovernmental Panel on Climate Change's
Fifth Assessment Report (IPCC AR5) assessed that the transient climate
response is 'likely' (&gt;66% probability) to be in the range of 1 °C to
2.5 °C.
By contrast, the equilibrium climate sensitivity (ECS) is defined as
the warming response to doubling CO$_2$ in the atmosphere relative to
pre-industrial climate, after the climate reached its new equilibrium,
taking into account changes in water vapour, lapse rate, clouds and
surface albedo. [...] The estimated range of ECS has not changed much
despite massive research efforts. The IPCC assessed that it is
'likely' to be in the range of 1.5 °C to 4.5 °C.

Which basically means that the climate will get warmer in the future, until it will eventually reach some kind of equilibrium.