<p>This study explores the impact of transient laminar fossil fuel thermophoretic convective heat transfer on climate change. To achieve this, a physical model is designed in which three regions are connected through trans-boundaries via temperature and concentration differences. Fossil fuel combustion emits thermophoretic particles in a rectangular coordinate source region. These particles travel through the plume region, represented in a cylindrical coordinate system, and then reach the atmospheric region, described mathematically using a spherical coordinate system. The main aim of this investigation is to analyse the time-dependent impacts of these thermophoretic particles on climate change. For this purpose, the non-dimensional model of all the three regions is separated into steady and unsteady (real and imaginary) part. These models are reduced to algebraic equations employing the finite difference technique. The solutions are achieved by applying a numerical method of differentiation to suitably chosen values of dimensionless parameters. The results, presented as graphs and contours, depict the effects on transient skin friction, transient heat transfer and transient behaviour of thermophoretic concentration. The contour graphs reveal that at <InlineEquation ID="IEq1"> <EquationSource Format="TEX">\(\alpha = 1.5\)</EquationSource> <EquationSource Format="MATHML"><math> <mrow> <mi>α</mi> <mo>=</mo> <mn>1.5</mn> </mrow> </math></EquationSource> </InlineEquation> rad, transient heat transfer is greater due to increased heat transfer, whereas transient behaviour of thermophoretic concentration indicates weaker particle deposition. At <InlineEquation ID="IEq2"> <EquationSource Format="TEX">\(\alpha = 3.14\)</EquationSource> <EquationSource Format="MATHML"><math> <mrow> <mi>α</mi> <mo>=</mo> <mn>3.14</mn> </mrow> </math></EquationSource> </InlineEquation> rad, transient heat transfer is weak and widely distributed while transient behaviour of thermophoretic concentration is greater indicating more particle deposition in horizontal directions suggesting increased pollutant accumulation in these directions. The main reason of this investigation is to analyse the transient impact of fossil fuels emission on climate change numerically and graphically.</p>