Projected impact of carbon dioxide (CO₂) removal from the atmosphere on radiative flux over West Africa

Solar irradiance is a component of the climate system that plays a major role in the global climate change phenomenon. Top of the atmosphere (TOA) radiative flux affects the temperature of the Earth’s surface and the atmosphere. In this paper, the impact of CO₂ removal on radiative flux at the TOA and surface over West Africa is investigated. A decrease in TOA downwelling shortwave radiations across the periods is simulated, signifying a reduction in warming at the TOA within latitude 14°N and above. Reduction in warming is projected in Niger, Burkina Faso, and Mali in the period 2020–2049 as TOA upwelling longwave radiation increased in these locations. Significant changes are projected more under clear sky conditions than cloudy. Removal of 1.13 ppm/yr (8.81 Gigatonnes of \({\text{CO}}_{2}\) ${\text{CO}}_2$ per year), 2.23 ppm/yr (17.39 Gigatonnes of \({\text{CO}}_{2}\) ${\text{CO}}_2$ per year), and 3.50 ppm/yr (27.30 Gigatonnes of \({\text{CO}}_{2}\) ${\text{CO}}_2$ per year) is projected for the periods 2020–2049, 2040–2069, and 2071–2100, respectively. Clear sky condition simulation shows a greater reduced level of warming before the end of the year 2100. Radiative flux reduction is projected far more at the surface than at TOA. Climate sensitivity and radiative forcing of −2.2 ± 0.1°CW/m² and −0.4 ± 0.1 W/m² are obtained, respectively. In contrast, a climate system’s response to forcing of \(\Delta T\) $\mathrm{\Delta }T$ = 0.88°C and \(\Delta T\) $\mathrm{\Delta }T$ = 3.76°C per unit decrease in radiative forcing are projected on global and West African scales, respectively.

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Most radiative parameters were reduced in each period compared to the reference period under both cloudy and clear sky conditions at the TOA. Significant changes are projected more under clear sky conditions than cloudy.