var CO2_model = {
    initialize: function () {
        this.pourcent = 0.43;
        this.an = 2065;
           },
    update: function () {
		this.taux = this.pourcent/100;
		this.CM = 1 + this.taux;
		this.ans = this.an - 2018;
		this.VI = 408;
        this.ppm = this.VI*Math.pow(this.CM,this.ans);
            }
};