The heat budget of the earth

Currents carry warm water to cooler regions and cold water to other regions. Link currents with heat distribution in exams.

Winds move warm and cold air masses and distribute energy. Consider winds helpful in heat balance for exams.

If energy input and output are not balanced average temperature may change. Link balance with temperature stability in exams.

Clear sky and low albedo allow more energy to reach and be absorbed by the surface. For surplus check input and absorption.

At night there is no incoming solar energy and longwave energy keeps leaving. Link nighttime deficit with radiational cooling.

Clouds and water vapour can absorb and send back terrestrial radiation. Treat them as night heat trapping factors in exams.

Through the atmospheric window some terrestrial energy can escape without much absorption. Link it with direct outgoing energy.

Clouds affect both incoming shortwave and outgoing longwave energy. Treat clouds as a dual role component in exams.

Urban surfaces with lower albedo can take in more solar energy. Understand the relation between urban surface and energy absorption.

Net gain shows energy surplus and can increase temperature. Understand net gain as energy surplus in exams.

Net loss shows energy deficit and can cause cooling. Understand net loss as energy deficit in exams.

Balance becomes clear only by comparing outgoing energy with incoming energy. Study both together in exams.

The thermal structure of climate is linked with energy input output and distribution. Treat heat budget as a basic climate concept.

Heat budget shows the full relation of incoming reflected absorbed and outgoing energy. Remember the whole sequence in exams.

Balance in the heat budget controls Earth's average temperature. Exam tip: treat it as the basic idea of thermal balance.

Hotter bodies emit energy of shorter wavelength. Exam tip: remember the relation between temperature and wavelength.

Higher albedo means more reflection and less absorption. Exam tip: connect albedo with surface brightness.

Clouds act both as reflectors and barriers in the heat budget. Exam tip: remember the dual role of clouds.

The heated ground emits energy as longwave radiation. Exam tip: connect surface emission with terrestrial radiation.

The direct answer is A: absorption of solar energy will increase. Dark surfaces generally have low albedo. They reflect a smaller fraction of sunlight and absorb a larger fraction, so their surface is more likely to warm. Reasoning: sunlight arrives; a dark surface reflects less; more energy remains in the surface; absorbed solar energy raises surface temperature and can increase heat available to the lower atmosphere. Option A is correct. Option B is wrong because strong reflection is associated more with bright, high-albedo surfaces. Option C is wrong because a colour change cannot make the entire heat budget disappear. Option D is wrong because the Sun continues to emit radiation independently of the surface colour. This is a general comparison; exact heating also depends on moisture, texture, clouds and angle of sunlight. Memory cue: dark means low albedo, less reflection and more absorption.

Oblique rays give less energy per unit area. Exam tip: remember the relation between latitude and insolation.

Direct rays concentrate more energy over a smaller area. Exam tip: connect low latitude with high insolation.

The atmosphere affects both solar and terrestrial radiation. Exam tip: understand it as a radiation filter.

Greenhouse gases absorb longwave radiation and maintain temperature. Exam tip: connect it with the natural greenhouse effect.

In long-term average Earth's energy input and output stay balanced. Exam tip: connect global balance with annual average.