Another sign of Graves' disease is hyperthyroidism, i.e., overproduction of the thyroid hormones T3 and T4. Normal thyroid levels are also seen, and occasionally also hypothyroidism, which may assist in causing goitre (though it is not the cause of the Graves' disease).
Without this greenhouse effect, the average surface temperature would be 255 degrees kelvin (-18 degrees Celsius or 0 degrees Fahrenheit); a temperature so low that all water on Earth would freeze, the oceans would turn into ice and life, as we know it, would not exist.
The greenhouse effect is essential to most life on Earth. If the Earth's atmosphere did not create a greenhouse effect, the Earth would freeze over.or planets, such as the Earth, which have an atmosphere containing gases that can create a greenhouse effect, there is always a delicate balance between the quantity of greenhouse gases in the atmosphere and the resulting temperature on the planetâs surface.