Final answer:
The term describing a future taxable amount caused by temporary differences between taxable and accounting income is a 'deferred tax liability'. This affects future tax payments due to initially lower taxable income reported. It highlights the impact on aggregate demand by temporary versus permanent fiscal policies.
Step-by-step explanation:
The term for a temporary difference that causes a future taxable amount if the taxable income will be increased relative to accounting income in the years when the difference reverses is known as a deferred tax liability.
This occurs because the firm initially reported lower taxable income compared to accounting income, leading to a situation where it will have to pay more taxes in the future when this difference reverses.
A temporary difference is a discrepancy between the book income and taxable income that will eventually be settled, affecting the timing of the tax payments. The concept is significant as it speaks to the differences between fiscal policy impacts, with temporary and permanent policies affecting aggregate demand differently.