fever — an abnormal condition of the body, characterized by undue rise in temperature, quickening of the pulse, and disturbance of various body functions.
warmth — the quality or state of being warm; moderate or gentle heat.
greenhouse effect — an atmospheric heating phenomenon, caused by short-wave solar radiation being readily transmitted inward through the earth's atmosphere but longer-wavelength heat radiation less readily transmitted outward, owing to its absorption by atmospheric carbon dioxide, water vapor, methane, and other gases; thus, the rising level of carbon dioxide is viewed with concern.
heat — the state of a body perceived as having or generating a relatively high degree of warmth.
fervor — great warmth and earnestness of feeling: to speak with great fervor.
fervour — great warmth and earnestness of feeling: to speak with great fervor.