In adiabatic process,

$∆Q=0$ and $∆U\ne 0$

Using the first law of thermodynamics, $∆Q=∆U+W$

$\Rightarrow ∆U=-W \left(W \text{is the work done by the gas}, \text{so} -W \text{will be the work done on the gas}\right)$

As the gas is compressed

$W <0$

Therefore, $∆U >0$ and hence $∆T >0$.