Scientists say that doubling pre-industrial carbon dioxide levels will likely cause global average surface temperature to rise between 1.5Â° and 4.5Â° Celsius (2.7Â° to 8.1Â° Fahrenheit) compared to pre-industrial temperatures.
Furthermore, they may experience withdrawal symptoms that can include headaches and irritability, perceived loss of performance both physically and mentally. People suffering with intolerance to caffeine have reported feelings of disorientation, loss of judgment, anxiety, dizziness, agitation and a hyper activeness.
Caffeine withdrawal symptoms typically appear 12 to 24 hours after abstaining from coffee, and peak within 24 to 48 hours. They include: headache; lethargy and drowsiness; depressed mood; anxiety; nausea; vomiting; muscle pain and stiffness; and inability to concentrate.