#### The concentration of carbon dioxide in the Earth's atmosphere is currently around  415 ppm. If the concentration of carbon dioxide were to reach 550 ppm, what would be the estimated increase in the Earth's average temperature (in degrees Celsius) due to global warming?Option: 1 $0.5\degree C$Option: 2 $1.0\degree C$Option: 3 $1.5\degree C$Option: 4 $2.0\degree C$

The relationship between carbon dioxide concentration and global temperature increase is complex, but scientists have developed models to estimate the relationship between the two. One commonly used model is called the Equilibrium Climate Sensitivity (ECS), which estimates how much the Earth's temperature will increase in response to a doubling of atmospheric carbon dioxide concentration.

According to the Intergovernmental Panel on Climate Change (IPCC), the ECS is likely to be between $1.5\degree C$ and $4.5\degree C$, with a best estimate of around c . This means that if the concentration of carbon dioxide in the atmosphere were to reach 550 ppm (compared to the current level of 415 ppm), we can expect the Earth's temperature to increase by approximately:

$\Delta T = ECS \times \ln (C/C_0)$

where$\Delta T$ is the temperature increase, ECS is the Equilibrium Climate Sensitivity, C is the final carbon dioxide concentration (550 ppm), and $C_0$ is the initial carbon dioxide concentration (415 ppm).

Using the IPCC's best estimate of ECS (3°C) and plugging in the values, we get:

$\Delta T = 3 \times \ln(550/415) \approx 1.07\degree C$

Therefore, the estimated increase in the Earth's average temperature due to global warming if the concentration of carbon dioxide were to reach 550 ppm is around  $1.0\degree C$(option 2). However, it's important to note that this is just an estimate and there are many factors that can affect the actual temperature increase, such as feedback mechanisms and other greenhouse gases.